11 Causes of a Car Losing Power While Driving Up Hills

Driving uphill reveals weaknesses that are hidden on level ground. Gravity works against you, forcing the engine to work harder. Accelerating now tests every component and if one part isn’t functioning like it should, your vehicle may suddenly struggle, hesitate, or even stall when going uphill.

If you car seems like it’s losing power while driving uphill, you need find the culprit because the problem is only going to get worse. Here are some of the most common causes to help you troubleshoot.

Read Also: Causes of a Car That Won’t Accelerate

Reasons Your Car Loses Power Going Uphill

1) Bad Fuel Filter

You can’t have a good working engine without fresh pure gasoline flowing into it at all times. If you don’t have a good fuel filter to prevent the impurities of the fuel from flowing into the engine, then it could ultimately jeopardize the performance of your engine.

Fuel filters typically have a service interval for when they must be changed. If the fuel filter is not changed for a long time, eventually the particles and sediment from the gas tank will build up and clog the filter, restricting fuel flow.

If the flow of fuel is restricted too much, not enough will be able to reach the fuel injectors and the car is likely to run lean.

2) Clogged Exhaust Components


The catalytic converter and the muffler serve as filters for the exhaust pipe, for harmful emissions and sound respectively. The muffler reduces the noise from the exhaust and the catalytic converter reduces the exhaust pollution.

If either one of these filters gets clogged, it limits the engine’s power and ability to accelerate. You may be able to drive slow on flat roads but once you get to an uphill road, you likely won’t be going anywhere fast.

A clogged exhaust can be dangerous, as it is a fire hazard in extreme cases. If you think your exhaust may be clogged, the issue should be addressed as soon as possible. Depending on what’s wrong, you may be able to clear it yourself.

3) Clogged Air Filter

dirty air filter

As much as the internal combustion chamber needs clean fuel, it also needs clean air to be mixed together with it to keep the engine powerful.

If you were to have a clogged air filter that wasn’t able to prevent impurities like debris and bugs from getting into the internal combustion chamber, then these impurities could end up damaging the engine.

It is important to have a clean air filter that is not clogged so air can continue to pass through the filter and enter the chamber without the impurities in it. Otherwise, the engine will never be powerful enough to make it up a hill.

4) Vacuum Leak

vacuum hoses

Vacuum leaks often only affect vehicles at idle, but if the leak is bad enough it may affect overall vehicle performance. A vacuum leak can be tested for using a smoke test to make sure the air intake system is sealed tight like it should be. A vacuum leak will make the vehicle run lean as unmetered air is enters the intake manifold.

5) Clogged Fuel Injectors

fuel injectors

Fuel injectors are the last parts before the combustion chamber in a long list of components that make up the fuel system

Injectors usually last for a long time, but they can become clogged with age or poor fuel quality as the fuel filter fails to pick up all the sediment from the gas tank. If an injector gets clogged, it affects the spray pattern and the injector’s ability to atomize fuel.

If the injector clogs completely or stops working, no fuel will reach the combustion chamber and no power will be made on that combustion stroke.

6) Bad Fuel Pump

bad fuel pump

If the fuel pump is on its way out, it may work intermittently or not at all. A symptom of starving the car for fuel is a car that runs correctly at idle and low load, but falls flat on its face as you ask for more power (when climbing a hill, for instance).

Fuel pumps may fail due to age, sediment buildup, or running the incorrect fuel. If you drive around with a nearly empty gas tank often, you may want to rethink that habit. Fuel is used to cool the fuel pump, and running with less than a quarter tank for long periods of time may reduce the life of the fuel pump substantially.

7) Bad Spark Plugs

dirty spark plug

As your spark plugs age, the spark gap can increase as the center and ground electrode(s) wear out. If this gap becomes too great, the spark may not always be able to jump the gap.

No spark means no combustion in that cylinder, which leads to misfires. This is a wasted combustion cycle where no power is generated.

8) Bad Ignition Coils or Spark Plug Wires

oil in spark plug well

Ignition coils and spark plug wires convert the low voltage power from the battery into the high voltage necessary to jump the spark plug gap. As ignition coils and wires wear, they may lose insulation and short out. When this happens, sufficient voltage may be unable to reach the spark plugs, causing misfires.

9) Faulty Camshaft Position Sensor

bad camshaft position sensor

The camshaft position sensor calculates the camshaft speed and transmits this information to the electronic control module. That way, the engine control module can manage the ignition timing and fuel injection timing properly.

But if you were to have a faulty camshaft position sensor, then the timing on these two would be off. This would limit the engine’s power considerably and certainly make it harder to drive the vehicle up a hill.

10) Low Cylinder Compression

low compression causes

Having high cylinder compression is critical for giving the engine enough power to get the vehicle up a hill. Once you start experiencing low cylinder compression, your vehicle will always be struggling on an incline because the engine power won’t be strong enough to push it up there.

11) Ambient Air Temperature

driving high altitude

If it’s really hot outside, your vehicle will have higher intake air temperatures. Higher intake air temperatures makes the engine more prone to knock. When the engine knocks, the computer has to remove ignition timing which reduces power and makes the combustion a bit safer for the engine components. 

You’re likely also running the air conditioning, which makes the engine work a bit harder.

If you’re driving at a very high altitude, there is less air to suck into the engine. Less air means the computer has to inject less fuel to maintain the proper air fuel ratio, so the car will not make as much power.

Altitude affects turbocharged vehicles much less than naturally aspirated and supercharged vehicles. In a turbocharged vehicle, boost will increase until the target boost pressure is reached. For other induction types, the intake pressure is based on mechanical constraints and cannot be adjusted by the engine computer.

12) Faulty Oxygen Sensor

Your car’s oxygen sensors play a vital role, constantly measuring exhaust gas oxygen levels. This data allows the engine computer to perfectly balance the air-fuel mixture for peak performance. But when this little gadget fails, acceleration suffers.

A bad O2 sensor disrupts proper fueling, sapping power as you climb hills. Don’t ignore warnings from this small but mighty monitoring device.

13) Limp Mode

limp home mode causes

Limp mode kicks in to protect your engine from harm, but leaves you crawling up hills. This safety feature detects issues like failed sensors or serious malfunctions. Then the engine computer limits power output, triggering sluggish acceleration and uphill struggles.

If you find your car slipping into limp mode, you’ll need to address the culprit ASAP. While limp mode is a symptom of a serious issue, it also itself causes a reduction in engine power which will be quite apparent when driving uphill.

14) Overheating Engine

An overheated engine inflicts uphill harm. Faulty cooling systems can’t properly regulate temperature, allowing your car to overheat and lose power. Watch the gauge carefully and address any overheating signs immediately.

Letting the engine run hot too long risks reduced performance and even stalling. Overheating issues demand prompt professional attention.

15) Turbocharger Problems


Your turbocharger boosts engine output, but component damage can trigger failure. A faulty turbo rotor, for example, disrupts normal functioning, decreasing overall power. This will be very noticeable with the extra power necessary to drive up an incline.

If you suspect the turbocharger of causing uphill struggles, have a qualified mechanic inspect it. In most cases, turbocharger problems are not a DIY job.

16) Clogged Diesel Particulate Filter

Diesel particulate filters reduce emissions but may clog over time. Accumulated soot particles can choke the filter, sapping power on inclines.

To prevent blockage, take regular long drives to burn off the buildup. If your filter is obstructed, replacement by a professional may be required to regain lost uphill capability.

17) Air Conditioning

air conditioning

Don’t underestimate your air conditioning’s toll on engine power. Turning on the A/C puts extra load on your car, sometimes causing uphill struggles or even stalling.

If engaging the cooling then saps your vehicle’s strength, try switching it off. You may find performance instantly improves sans AC’s burden.

18) Transmission Problems

Transmission troubles translate to uphill struggles. Climbing a slope demands extra power, which a faulty transmission can’t deliver. Slipping gears or improper shifting prevent reaching the ideal ratio for maintaining speed on inclines.

Your engine’s full force never makes it to the wheels. Instead, momentum melts away as a malfunctioning transmission robs your car of its uphill might.

Things to Remember

If you start to have acceleration problems as you attempt to drive uphill, do not slam down on the gas pedal to try to get up the hill. You will only put more stress on the engine which won’t do any good if there is an issue somewhere in the engine.

The best thing you can do is to avoid driving on severe inclines only until you can get to a repair shop. But if these problems get any worse, then even driving on flat roads will eventually become a challenge too. It all depends on how long you let the problem continue to last.


76 thoughts on “11 Causes of a Car Losing Power While Driving Up Hills”

  1. 2016 Hyundai Tucson losing power up the hill. My search led me various cleaning products to deal with the GDI engines – for example CRC all the way to distilled water vapor. Do these work?
    No engine light. Found alot of squirrel activity underneath the air filter. Changed filter. Did not improve, but I am wondering if we did not remove all of it as the intake looked longer than my vacuum hose. I would like to be sure that this step is executed completely. Any suggestion about how to get all the way down the intake?

    • I don’t know if they will help in your specific situation. There could be further squirrel activity somewhere in the intake you can’t see, and I would start there.

      Probably the best place to look for that is YouTube where someone is changing a throttle body, that should show you how to remove most of the intake components. I doubt the squirrel made it past the throttle body but you might be able to open the throttle plate and look for debris in the intake manifold as well.

  2. 2017 ford fiesta se not going uphill is this normal. I tried downshifting for extra power because my cruise control wouldn’t rock up then my car started to make this bad smell. Felt as if there was a lot of resistance in the engine

    • I wouldn’t say that’s normal, no. You’re probably going to spend a bit of time diagnosing the issue. Start with codes, check the basics like making sure the air filter was recently replaced. Make sure you’re running good fuel, make sure your spark plugs are good.

  3. My vehicle can’t climb up hill. I have tried all the possible cause, but non. I have just put pressure plate and release bearing. Somebody adviced me, it is possibly flywheel. Could flywheel make a vehicle not to go uphill?

    • It’s possible, but I would typically blame the clutch before the flywheel. You might have to drop the transmission to check your work, or take the vehicle to a shop to have them diagnose the issue.

  4. My car has the following issues:-
    1. Loses power when driving uphill
    2. Show check engine and steering once in a while
    3. Returns water to reserve tank when accelerating
    Anybody who have ever experienced such, kindly help

    • Number 3 issue, is normal when the engine is hot and the radiator pushes excess water into the reserve tank when accelerating. The water will return back to radiator when the engine is fully cool down.

      Number 2 issue might be due to your catalyic coverter clogged that trigger the o2 sensor light, therefore, losing power when going up hill.

  5. Hello , I have a Vauxhall astra 1600 j 2012 car , it slows down only on very steep hills. I have been told that the car is a lot heavier than the astra 1400 before it that I had no trouble with up steep hills
    .it’s the weight of the car that slows it down. Change down !

  6. I have a Nissan Almera, having difficult struggling to drive uphill and sometimes causing traffic jam. I have read the 11 clues and will try to attend firstly fuel filter and next say fuel pump, if the problem persist will consider the next clues from the 11.


  7. I just read the 11 things and would like to add one more. I had the same problem with a 2004 Pontiac with 117K miles V6 engine. Fine in town but slowed to 30mph on the hill to get home. Reading about the air flow made me think of the Mass Air Sensor which had recently clogged up on 3 different vehicles of friends. We had the spray cleaner in the garage and my husband just gave it a try. Off I went to town, the road with the most hills and back, no problem. Fingers crossed this lasts 🙂

  8. I Have ford figo diesel 2011 model and I drive this car in hilly area then I saw that their is a problem to go upward it go 20-30 maximum speed and want to change gear 1 or 2 between these gear I reach to my destination but it can’t get speed more than 30

  9. My name is Cyprian, I drive an X-Trail T 31. When cars has poor acceleration at low speed and when uphill. One feels like the acceleration unit is failing. What could be the matter.

  10. Model : xzb50r-zemsyq
    Toyota Coaster
    Hi, I am currently working with a company which the company has two same Toyota Coasters. So one of those two Bus has a lack of power going up hill?

    My Mech checked and Change the Fuel Filter, Clogged Exhaust Filter ,Clogged Air Filter,
    Fuel Pumps but still having the same problems

  11. Hi my vauxhall vivaro van has problem to drive uphill for quite a while especially on motorway. I usually topup the oil level about half pint then driving uphill fine on motorway around 120 miles. But now the oil level is almost on maximum that i cant add more oil. I am wondering whats the reason cause the problem. Thanks

  12. I have ford everest 2007 model hard to climb uphill i need to shift in 2nd or first gear and rpm too long in order to run or climb. And hard to get an 80 kph

  13. Hi I have Opel Astra Essentia my car is failing to climb on the hill and it showing an engine light and my AIRCON is not working it give me an hot air.i took it to diagnose and they said it an airflow sensor that was faulty so they cleared it but still my aircon is not working and still failing to climb the hill. Even when get to 120 speed on the hill I will finish the hill with 50 speed with 3rd gear

  14. My Volkswagen Passat 2.0 Automatic began to drop slow while climbing hills, but move normal and fast on a flat ground. I’ve change fuel pump, fuel filter and air flow meter, yet the problem persist. What should I do?

  15. My car jerks at slow or in traffic, it, d jerking, stops if I put it in Neutral but begins whenever I put in drive or reverse. Finds it difficult to drive up hill but runs well on flat ground. Now it can’t even climb d hill it usually climbs.
    I bought it from someone, I noticed that the injector mouth was blocked at the small hole in it, when opened the vehicle works high. But was advised to replace it. Plugs changed.

    Now i am looking at replacing d fuel pump, and replacing the injector mouth

  16. While I found the info interesting, the majority of it wouldn’t apply to my 1979 Subaru Brat.
    I will change the Fuel Filter & Air Filter but, if that doesn’t resolve the problem I am going to assume it is because of High Altitude. I live at 6000 ft & my favorite Trout stream resides above 8000 ft.

    • I’m sure the elevation has something to do with it; those cars didn’t come with a ton of power from the factory. You could always try doing some basic tune up tasks to see if that helps breathe new life into the vehicle.

  17. Hi, I drive a Stringray 2016 J-style, so while driving I get the autostop sign, and when I stop in a signal or press the brake the car engine turns off and it fully stops after few mins I start the car and works fine but again I get it after I drive like 200M. I did full service changed oil everything was fine I just don’t know how to stop the autostop. any solution for this please?

  18. I have a 92 gmc k1500. new fuel pump, new coil, icm, distributor, coolant tem sensor among other things. the guy that put the distributor in also set the timing but since then it runs sluggish especially going up the hill to my house. I put it in 4wd and it went up fine which doesn’t make sense. It also has new plugs and wires. If the timing is off would that cause the problem? it runs good out on the highway though it still doesn’t seem like it has the power like it use to.

  19. I have a 1988 honda cicvic.I went up a hill on the freeway and my car started jerking and slowing down. I had to down shift several times to get over the hill. On level ground it runs fine.What can the problem be related to.Had a tune up about 2 months ago. and said head gasket is leaking a little. Can this be the reason?

    • I’m not sure. A compression test and leak down test will tell you a lot about the health of your engine though. Check for codes, use that to help you narrow down the problem.

  20. I drive a hyundai sonata gls v6 2000, so the car drives fine on flat road and the only issue i got is when driving uphill it doesn’t accelerate and with difficulty it pulls up. any solution for this please?

  21. i own an 08 jeep liberty and ive been noticing that im starting to lose 5 to 10 mph going up hills, just basic inclines like on the interstate.

    • Could be a lot of things. First take a look at the spark plugs if they haven’t been replaced in a while. Spark plugs are a cheap and easy fix. If new plugs doesn’t help, more diagnostic work may be needed.

  22. You forgot “electric system.” We had a Dodge Aries that went dim on its lights a few times and went into the shop for electrical work. Then I started driver’s ed. Coming up a big hill one practice drive, it started kicking like a mule when I gave it gas. Had to crawl up at 30 mph in a 45 mph speed limit. Back in the shop because the fuel pump wasn’t getting juice–though we didn’t notice it unless the pump had to push gas uphill.

    Good learning experience, though. Gets yo afeel for what you’re right foot’s doing.

    • It’s true, if the electrical system is messed up in a way that prevents the signal from properly reaching the fuel system components (injectors, fuel pump, etc) from the ECU, the vehicle could struggle or die. This could happen due to an electrical short or a bad ground.

  23. I have am automatic Ipsum, It has no pulling and sometimes it goes off especially on higher gravities, I changed the fuel pump, spark plagues, but still having same problem when I accelerate it jumps to a higher gear but moving very slow.

  24. My automatic car Toyota Ipsum has lost power both on flat and uphill. On engagement of the drive gear the car can’t move until I press hard on accelerator. When going uphill it’s too hard and at times stops. I don’t know what could be the reason.

    • I’m not sure. You could start by changing the spark plugs and wires if they haven’t been touched in a while, and doing a compression test while you’re in there.

  25. I drive a 2000 Mustang. Moved to Kentucky and have to drive up hills a lot. My car started being sluggish trying to go up the hills. Any suggestions.

  26. Hi all, I drive a Navarra truck whilst in Devon I found the old girl struggling to climb hills and kicking out a lot of black smoke generally she runs pretty good just a bit of smoke on pull away any advice would be very helpful thanks in advance

  27. It’s probably a spark related issue. I’d try plugs & wires first and then coil packs (distributor cap & rotor on older vehicles)

  28. My 2end bought car got two main issues unsettled remaining to be advice for better recovery please:
    1. The consumption of fuel is very fast thus cost me a lot of money on fuel, and also fuel smells coming out of excesspipe while engine is on running

    2. My car got problems in climbing the uphill or mountains and its very slow or engine becoming powerless, while driving on the flat land its speed is more likely of those new cars.

    Therefore, I urgently need some possible advice or recommendations regarding this issues with my car.

    • It sounds like your car is running really rich. Is the check engine light illuminated? If so, I would suggest getting your car scanned at your local auto parts store. Many auto parts stores will read the code(s) for you at no cost. The parts store staff may even have suggestions for next steps you could take.

      Unfortunately it’s hard to provide much more information than that without knowing any details about the vehicle.

  29. My car can’t climb up a hill after I changed a worn out double head spark plugs with a single.
    Before the change of spark plugs my car loses power whilst it still running. The other day I can’t start it till I changed the spark plugs. Thought issue is gone but now I can’t climb mountains

  30. I have a Hyundai creta ix 25 2015 or 2016. I noticed a week ago it was not accelerating well I went to the mechanic he said fuel pump it needed to be cleaned which was done., few days again noticed it was not climbing well mechanic said spark plugs cleaned it. Today it still did not climb well he said he had to flush the catalystic converter which he has done still no improvement my car is still struggling.

    • First thing he should have done is scan the car for any trouble codes. Maybe he did but it almost sounds like he’s going on a wild goose chase and replacing whatever he thinks it could be. Unless you left out a lot of details, I’d be looking for a new mechanic.

      • About a week ago my opel vectra C 2.2 doesn’t go faster as it was when climbing a hill, it goes alright on a level ground, what do I do please?

      • That depends on why it’s not climbing hills. It could be a slipping clutch, or perhaps down on power from pulled timing or misfires. You’ll need to do some digging to know for sure what your options are.

    • take it to another mechanic .one that wont tell you he can flush a catalytic converter.the inside of a cat is like a mesh with a honycomb pattern the little openings become clogged with carbon and molten metal and simply cant be flushed[,observations of many failed attempts]the cat must be replaced and if that is your problem,do it a clogged cat will create so much precat heat that it can cause severe engine damage

    • He CLEANED the fuel pump and plugs and then FLUSHED your CatConverter? What kind of mechanic did you find yourself? Got his ASE out of a cracker jack box?

    • I had got the same issue n when I referred a mechanic he changed the clutch shaft n clutch bush..when I tried a test drive with him the hill climbimbing was now not an issue….

  31. Thanks. This difficulty occurred last night going up a long incline happened last night when road was slick with rain. When I got home about 15 minutes after making the slow incline, I parked the car in the garage and it continued make a long groaning sound after the car ignition was turned off. This morning I got up and turned on the ignition and started to back out and, during a few feet, I perceived some jerkiness in the car’s movement. So I put The car back in drive and parked the car in its usual spot. Which of the 5 issues do you think I have with my Volkswagen Passat 2007? I rarely drive Since ai am elderly (74 years old) I have about 64000 miles on the car since I purchased it new in 2007.


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