How to Diagnose a Failing Fuel Pump on Your Car

The primary symptoms caused by a failing fuel pump and other problems that can produce the same or similar symptoms.

When the fuel pump is working right, you will not even know that you have one. However, if it fails, you will be left stuck on the side of the road about to have your wallet emptied for a repair bill. Years ago, mechanical fuel pumps would cost you about $20 for the part and $30 to $50 to have it put on the car. Today, electric fuel pumps that reside inside the gas tank will cost you $200 for the pump and about the same to have it installed.

If you can learn the warning signs that the fuel pump is starting to fail, you may be able to spare yourself the part about being stranded. In fact, if you are handy with tools, you may be able to save the labor bill, too. Weak fuel pumps are not always easy to diagnose in by a mechanic. The reason for this is that when they are first starting to fail, fuel pumps falter intermittently. They also tend to manifest the problem at highway speeds rather than at idle.

The warning signs of a failing fuel pump are not hard to identify. The problem is that they can mimic other problems in the early stages. It is common for people to makes serveral lesser repairs before tackling the fuel pump. The expense of this big ticket repair scares most people away until there is no other choice.

Your engine will seem to miss at highway speeds.

A engine that misfires will cause the car to jerk occasionally while going along the highway. Frequently, the fuel pump will falter for a mile or so two or three times and then run fine for the next 50 or more miles. This type of problem can be misdiagnosed as a bad spark plug or plug wire. In some cases, you will just be told that you probably had a little moisture in your tank that caused your fuel filter to act up. A mechanic may even persuade you to change the filter or get a tune up.

Your car will lose power as you pull away from a standing stop.

You push down on the accelerator, and the car starts to go and suddenly seems like it is going to die. Immediately, it seems to restart and off you go. This type of problem can be thought to be an oxygen sensor failing. Since this is a quick but not always cheap fix, you may opt to give it a try. This same type of symptom can be caused by your smog control devices on the car. A final possibility is that the distributor or coil is not working properly. About 75% of the time, this will turn out to be the fuel pump.

You lose power at highway speeds especially when the car is climbing a hill or under a strain.

This problem is almost 100% of the time caused by a fuel system failure. The fuel filter is the first culprit. Once this is ruled out, the fuel pump is the next best bet. The difficulty here is that this type of failure can be intermittent, too.

Your car cranks when trying to start it, but it does not hit or start.

Two issues cause this problem. The first is the timing belt or chain has broken. Without a timing belt, your car will turn over, but will not start. Almost any mechanic will not have a problem figuring out which one it is. Most cars have an inspection plate to view the timing belt or chain. By taking a look inside, the mechanic can determine if the belt is alright. If it is, the problem is the fuel pump.

When several of these symptoms occur over a short period of time, you should seriously consider that it is the fuel pump. Taking early steps to have it replaced or replace it yourself will save you frustration and possibly some cash.

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  1. I have an 81 Triumph TR-7 with symptoms above. The fuel pump is very noisy (whiney). Since this model of TR is utilizes Boch L-Jetronic FI and almost 30 yr old, I plan to replace both the filter and pump at the same time… approx $100. I will let you know the results!

  2. i have a fuel pump stop woking on a friend and it didnt make no nosie and had no problims with it but it just quit for no reason and nothing above on here was helpful bc it wasnt right

  3. Dominic: There are a couple senarios to this. One: If it’s an electric fuel pump, I’d check to see if a ground wire or coupler wire became disconnected. Check to see if you have voltage to the pump. Check the fuel pump fuse. Second: If mechanical, Check to see if a vacuum hose came off or if the diaphram is leaking. Then I would check the actuator arm.
    It sounds more like a electrical problem though since it just stopped suddenly.
    Good luck!

  4. I have a 2000 Chevy Silverado Z-71 4×4 with the 5.3L And when its cold the engine has no throttle power if you step it down from a stop, after it warms up about 3 to 4 minutes it seems just fine. Could this be caused by the fuel pump being weak? O2 Sensor? Air intake temp sensor? Im kinda at a confused point now about this.

  5. I’ve waited as long as I can to replace my in-the-tank fuel pump on my 1998 GMC Suburban (350). I’ve replaced BOTH catalytic converters, all FOUR O2 sensors, plugs, wires, rotor, fuel filter, PVC, coil…and yes, it’s still spits and sputters when I try to accelerate too fast. From what this article says, it’s time for me to break out the plastic and cough up another $300-400 for a new pump.

    Question: If an aftermarket (Ebay brands) just as good as the one you can get at the dealer?

  6. I recently took my 98 chevy blazer muddin and since then it will start and idle fine but the fuel pump is extremely loud and whiny and it barely will get up to and hold 45 mph. the engine wants to bog bad. i have replaced the fuel filter, air filter, distributor, and let it idle to push out any moisture or atleast let it dry. i drove it yesterday and it drove fine, but today it wont rev and the engine bogs some what again. like i said the fuel pump sounds like it wants to explode and sometimes like its gonna give out, but the engine seems perfectly fine. does it need a new fuel pump?

  7. I just dropped my 01 altima off at a private mechanic. It was running fine, When he started it up to move it to his driveway, it died a few seconds later. he called me back right away. There were no warning signs at all. Is it possible for the fuel pump to just quit like that?
    I have trusted this guy up to now, but am beginning to wonder if he staged this to make it look like a fuel pump failure..

  8. I replaced the fuel pump in my 93 silverado w/5.0; put a tuneup kit the the fuel injector throttle body unit, still no power to the pump. pump checked w/12v in tank and works fine, is there a relay or any other electrical device that can prevent the pump from working?
    chris

  9. I have a 1999 ford Taurus, we are not sure exactly what the problem is. Sometimes the car will start, sometimes not. Once it is running, we have no problem with it. When the key is turned to the on position, and you can here the HMMMMMM from the fuel pump I assume priming, the car will start right up. BUT sometimes it take quite a few tries of turning the key to the ON position for the pump to make the HMMMMMM sound. Is it the pump on it’s way out, or something maybe electrical ?

  10. I have a 2001 Sable (Taurus look-alike) and it is doing the same thing. I tried replacing the fuel pump relay under the hood, with no improvement. Problem seems worse when cold (not always) and if it has set for several days (not always.) …..Still trying to determing the problem. Be sure to post if you solve this.

  11. I have a 2002 Mercury Sable, my wife was driving it and bam the fuel-pump just took a crap..besides the car starting really hard and just throttleing then dieing there were no other symptoms. I took the fuel-line off just before the first filter and using a mason-jar was able to measure how good the fuel-pump pressure was by turning the key and it barely pumped any out..one of way of knowing the pump is weak or bad.If its getting power you can usually here it energize..but the fuel-pump is also pretty easy to do, hardest is dropping the gas-tank..might want to drain it first.

  12. i’m using a mazda familia 99 model. it jerks at a speed above 140km/h and at times reacts seconds later to accelarator pedal push especially when fuel tank is quarter empty. do you think i should replace the fuel pump?

  13. this article has me leaning towards fuel pump. I couldn\’t start my car this winter and changed the Ignition control Module and the Computer. since then I have changed the spark plugs and wires. I changed the plugs and wire again because it stalled at work. It didn\’t work so I put a new EGR valve on and started right up, the old one was decrepid. Also put on a new fuel filter as a precaution, it also just really needed to be done. now I have a cracked exhaust manifold and I\’m constantly patching it. I just spent every last dime on new drums that were falling apart and leaking like crazy and lost my spark plug socket to check the plugs but you know. It sounds and feels like a cylinder missing, but the intermittency and the fact that now the problem is here for real. I think the mechanic who did my brakes might have had a little too much fun driving my car and pushed it over the edge, asking it to accellerate more than I ever would have. It\’s definitely worse up a hill, and at initial accelleration, but it\’s even worse while idling or switching from drive to reverse. could this be related to the transmission. It shifts between gears just fine (I know exactly where the switches are occuring ) Tranny fluid looks decent still. I just got it installed and only put about 6000 miles on it and I don\’t know what was on there before. otherwise, before I changed the EGR valve there was light soot on my spark plugs and I changed them and also the air filter but now it\’s dirty again already. I do a lot of driving so maybe that\’s just the price I pay, that was about half an oil change ago because I\’m due for one so I\’m not tremendously surprised about the air filter, but is it the reason I\’m stalling. I have no money and can\’t convince myself a filter is causing my car not to run correctly. I have to put all my resources on one repair

  14. I have a 98 Chrysler Concorde LXi. When I am accelerating from a stop, or just from a low speed, I hear a rattling from underneath my car, close to the trunk. Does this indicate a failing fuel pump? If not, what is the problem or any ideas???

  15. I HAVE A 2000 HYUNDIA ELANTRA. I PUT A FUEL PUMP IN TODAY AND DID NOT HELP. THE CAR BUCKS DRIVING DOWN THE ROAD AN CUTS OFF. SOMETIME YOU CAN DRIVE IT 60 OR 70 MILES BEFOR IT ACTS UP. SOMETIMES IT WONT START WHEN ITS HOT. LET IT COOL OFF IT WILL START BUT STILL BUCKS AN STALLS OUT. PLEASE HELP

  16. I am having the same problem and i am on my second starter and the fuel pump sounds like its dieing. N when i am making a sharp turn or a turn period when the gas is on the quarter mark my car cuts off or starts to studder like it wants to shut off

  17. How do you diagnose a fuel pump problem on ‘99 Jeep Cherokee? The vehicle was stalling out on me yesterday.

  18. How do you diagnose a fuel pump problem on ‘99 Jeep Cherokee? The vehicle was stalling out on me yesterday.

  19. why not just put a fuel pressure guage on your car and check the pressure then you will know

  20. I have a e 350 cargo van. Seems that when the gas tank get below half the truck starts to miss and surge. Replaced the fuel pump and it stopped, but now is doing it again

  21. Replace it yourself,,,,,,I like that. I wonder if the guy who wrote this article ever tried to crawl under a 98 chevy truck with a 5 foot long, 34 gallon gas tank, half full with rusted bracket bolts and a rusted up sending unit from Michigan road salt. Now if you have a hoist in your garage, a trans jack and an air compressor with a cutting wheel, OK, but the average joe aint replacing an electric fuel pump in his driveway with hand tools. Save yourself the trouble and let a pro do it for $200 in labor cost.

  22. I had that problem on a 97 chevy truck. A friend of mine replaced the fuel pump with a new sending unit and when the tank got below half, it would surge, buck on initial take off. Come to find out, he left the “sock” off the end of the pick up tube. It acts like an accumulator . He dropped the tank, put the sock on it and it ran fine. That “might” have something to do with your problem.

  23. i have a toyota avalon, when driving your it the power will shut off and have to restart it again; can this be the fuel pump?

  24. My 1978 Lindy Motorhome with a dodge 360 engine is still chugging, most noticeably going up hill. I had the mechanic change the fuel and air filters and adjust the carb. Still having the “chug” problem. Any thoughts or suggestions ons? Could be the fuel pump from what I’ve read from other commenters.

  25. Was it the fuel pump? we have exactly the same problems

  26. I have a 2000 hyundai elantra. I was driving and all of a sudden my car shut down on me and I replaced the fuel pump it works while your trying to start it, but its not priming the fuel when the key is in the on position. Engine is turning over, but wont start

  27. Toyota Seinna 2002 What could be the cause, that it failed to climb the hill and accelerate as need i have to revised and trying climbing up the again, again before it manage to climb thru.

  28. I have a 1995 Signature Town Car. I shut the car off, when I came back out 15 minutes later the car just cranked and wouldnt turn over. I checked the fuses under the hood, I checked the auto shut off in the trunk, nothing. I called a towing service, when we pushed the car out of the driveway it started (go figure). a week later it happened again, I was parked on a slight decline, after a few minutes I let the car roll about 20 ft to a slight incline after trying to start it for a few minutes it started. Im thinking a clogged strainer or something in the tank or a clogged fuel filter.
    Any thoughts
    Ernie

  29. I have a 1999 Civic and, guess what, I have absolutely no probems! It runs like a charm!

  30. LOL alot of questions here about there car, but rarely if any answers..lol.. so will not waste my time posting my question just for it not to be answered..hahhahah

  31. I have a 2000 Mazda protege that jerks and stumbles when going uphill. Runs fine on a straightaway. Mechanic installed new plugs, wires, coils. I still have the problem. Could this be the fuel pump?

  32. my 2001 f150 fuel pump stop working I just replace it 6 weeks a go the truck was running fine started fine it was in the driveway wen shut off end is like 1/2 tank of gas on it

  33. These are correct. Good symptoms to look for. Make sure to get a good replacement or you will end up having to use a hand fuel pump. lol

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