Repair Topics / Car Engine Runs Rough-1 / Car Engine Runs Rough-2 / Car Engine Runs Rough-3 / Car Engine Runs Rough-4 / Car Engine Runs Rough-5 / Car Engine Runs Rough-6

Car Engine Runs Rough and Idles Questions

Question:   2003 Mazda MPV 3.0 V6 mileage 62,000: My Mazda has developed a really annoying engine fault. When the engine is cold and running on choke (or whatever fuel injection engines do) it runs fine. But as the engine warms up and it comes off choke it coughs and splutters, the engine dies. It then refuses to restart - the engine turns over but makes no attempt start. After leaving it for 20-30 minutes it will reluctantly start and then once it's up to temperature it doesn’t miss a beat. Alas I am quite confident of doing a 300 mile journey without any problems but know that if I just want to pop to the shops round the corner the van will breakdown. My local garage have tried replacing the spark plugs, air flow sensor, coil and ignition sensor - none of which have resolved the problem. My friendly mechanic is now lost for ideas and suggested that I ask you friendly folk for help. Please help - I love my van but it’s worthless if I can't fix this problem.

Answer:   Scan the computer for fault codes. If fault codes are found repair as needed. If no codes are found check for major vacuum leaks and repair as needed, recheck.

Question: 2003 Ford Mustang mileage: 68,000. My car acts very sluggish when it's cold or warm, like it hits about 2600 rpms and stops pulling. But, when the car is hot, it works fine. I'm also getting a check engine light reporting lean fuel mix. I've replaced fuel pump, filter, regulator, and 02 sensors, checked TPS, replaced everything to do with the ignition system, lots of other stuff to long to put here, but the problems continue. My fuel pressure is steady @ 32 and vacuum is steady at 15 hg (est. 4000 ft above sea level). Do you know what this could be?

Answer:   Replace the MAF sensor with a new sensor and you're problem will go away, plus your car get better mileage and performance. (Mass Air Flow MAF sensor or Air Intake Sensor AIS, depending on manufacture. It does the same thing with different names).

Question: 2004 GMC 1500 Sierra.  I am having trouble starting the truck.  It is rough running when it starts since I did the tune up.  Thank you I hope you can help.

Answer: Try checking the fuel pressure regulator, its sounds like the diaphragm has failed and needs replacing to repair the problem.

Question: 2001 Mazda Tribute mileage: 102,000.  I recently replaced the upper radiator hose, spark plugs and wires. When I started the car, it idled rough and would jerk upon acceleration.  I re-checked the spark plugs for proper gap, checked the wires for connection and the firing order.  All was correct.   My muffler has a couple of small holes in it and someone said it might be the catalytic converter clogging up.  I think I knocked off a vacuum line.  What do you think?  I am afraid to take it to a mechanic, because most see a woman coming and see dollar signs (no offense).  I like to do my own repairs and have never been stumped like this before.  Thank You

Answer:  Check for a failing fuel pump, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 2004 Isuzu Ascender 5.3 V8 mileage: 54,850.  For the past 2 weeks it has, every once in awhile ‘sputtered’, now it does it all the time, especially after driving it awhile and more so, going up hills.   It does not seem to do it as bad when I get low on gas...of course, everyone has an opinion.  It’s the fuel filter, timing belt, oxygen sensor. etc...the best advice I've received so far is to take the car in, but I'm afraid of getting ripped off because I am female (please help.  (Oh yeah, 'sputtering' isn't the best description; more like um...it bucks and looses power?)  I don't know how to describe it.  Anyway there ya go.

Answer:   It sound like you need a major tune up including spark plugs, spark plug wires, fuel filter and air filter. Replace as needed to repair problem.

Question: 2000 Chevrolet Astro mileage: 161,000.  My car is not running smooth when I go up hill.  The engine jumps, I call it the put-put sound.  My mechanic ran a diagnostic on it and nothing was wrong.  The engine light does not come on.  When he looked at it he said it had phosphorus burns and fixed the timing, replaced the rotor and distributor cap, but it is still doing it.  What can the problem be?

Answer:   It sound like you need a major tune up including spark plugs, spark plug wires, fuel filter and air filter. Replace as needed to repair problem.

Question: 1997 GMC 1500 4x4 mileage: 152,000.  When stomp on gas it feels as if you are dragging an anchor, ok with light acceleration.  Also, sometimes will pop in intake.  Seems like lean fuel.  Fuel pressure & volume ok.  SES light was on.   I replaced one oxy sensor & light went out, but problem still there.  No trouble code comes up on scanner.

Answer:  Check for a failing fuel pump, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 2003 Toyota Tundra 4x4 mileage: 99,000. For the past two-three months my trucks rpm's have not been consistent.  It fluctuated even when I did not accelerate the engine. In the past two weeks, it has been getting worse.  A few days ago when I got onto the freeway and experienced a craze with the rpm’s as I changed gears.  Ultimately, I was stranded on the side of the freeway.  I changed the clutch as my mechanic advised and it has gained a kick when I shift gears.   The rpm's still fluctuate slightly on neutral, first or second gears.  Once I get going it is not a problem.  Obviously, the clutch was not the source of that problem.  I am assuming it may be the fuel pump or filter.  What do you think the problem could be?

Answer:  Yes, the fuel pump sounds like it is failing, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 2004 Ford F350 mileage: 80,000.  Truck acts as if it runs out of gas - changed fuel filters, checked timing, gave complete tune-up and changed fuel pump relays. Gas is not getting to injectors; what else could it be?

Answer: The fuel pump sounds like it is failing, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 1999 Olds Cutlass mileage: 94,000. Runs fine until restarted after driven in stop and go traffic or long idle.  No warning lights or trouble codes set.  Service station smog test pass and run fine.  HELP 

Answer: Your car is ready for a tune up including spark plugs, spark plug wires, fuel filter and air filter. Replace as needed to repair problem. Some cars will pass the smog check even if that need a tune up.

Question: 2002 Suzuki Esteem 1.8 DOHC mileage: 77,000.  I have a miss. Cylinder 4 is not firing.  I have replaced plugs, no change.  I have been told by repair shop igniter needs replaced, done, no difference, now repair shop says need computer.  I live in PA.  Dealer where I bought vehicle in WV says computer not the problem.  Each cylinder has its own coil pack with plug wire attached, could this be the problem?

Answer: Check cylinders compression, if ok. Try replacing that cylinders coil with new. Also check the fuel injector for that cylinder, replace as needed.

Question: 2002 Honda Accord mileage: 87,000.  My car starts off well when it is cold but the moment it warms up the engine loses power. When I warm it up in the morning for more than 2 minutes, the engine does not respond when I step on the accelerator pedal. I will have to keep pumping it for the car to move. When I drive off and start reaching like 70 miles/hr, it begins to hesitate and the engine stops responding to the accelerator pedal. After slowing down to about 45 miles/hr, it begins to respond again. Holding the accelerator pedal to the floor yields a positive result sometimes. It has a carburetor and I have been told 4 times that it is no problem by my mechanic who also gave the car a complete tune-up. Now they are telling me it is the distributor. However, this car has traveled to NYC from NH 2 times. Please help.

Answer:   Check the catalytic converter for blockage. It sounds like the catalytic converter has failed and is blocking the exhaust system. Replace catalytic converter with new to recheck system.

Question: 2004 Ford Explorer 72,000 miles.  My boat and trailer weight 1950.  When I get home and unhook the boat form the truck, my engine is idling rough.  Later after, it cools down its normal.  What is causing it to do that?

Answer: You could have an injector that is failing when heated, scan PCM to check history trouble codes to repair failing cylinder. Replace to repair as needed.

Question: 2002 Ford Explorer mileage: 90,000.  Would you be able to tell me where to look to fix my truck? First of all, it idles rough, then when I put it into gear it stalls, there is black stuff on the ground after starting it and letting it run a bit.  The spark plugs and wires are new, also replaced the cap and rotor.  It almost idles like its got bad fuel in it, but I put fuel treatment in it and that didn’t help.... Please tell me where to look next.

Answer:   This is difficult because the computer can't detect a problem, your van thinks everything is ok. In reality what is happening is the electrical component inside the MAF sensor becomes contaminated by the impurities in the air (heavies) These containments imbed themselves to electrical component that senses the air flow causing the sensor to be slightly off, but not enough to trigger the MIL (malfunction indicator lamp). Replace the MAF sensor with a new sensor and you're problem will go away, plus your car get better mileage and performance. (Mass Air Flow MAF sensor or Air Intake Sensor AIS, depending on manufacture. It does the same thing with different names).

Question: 2002 Ford Escape, miles: 85,900 It started running a little rough and the next day died on the way to work. I got it started, but it would only idle and the gas pedal did nothing unless you kept it all the way to the floor and then it would begin to rev up after a minute or two. It would then rev up and down normally until I let off on the gas peddle and then it would only idle again. I changed the fuel filter first and that did not help and then I changed the fuel pump in the gas tank and that did not help either. This is a fuel injected engine. What else can I do?

Answer: The fuel pump sounds like it is failing, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 2001 Toyota Camry, miles: 67,000. For the past two weeks, every time it rains or is very damp my car is hard to start, runs rough, and hesitates on acceleration and stalls. Once everything dries out the car runs fine. I replaced ignition cables, distributor cap and rotor but problem continues. Thought I'd check with you before I take it to the dealer.

Answer: The fuel pump sounds like it is failing, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 1999 Toyota Camry mileage: 180,000. Car is sluggish when accelerating and going up hill, I'm guessing it’s a fuel filter cause that's the only thing I think I could fix. How hard is it to replace the filter. Any other thing that might cause sluggishness, car seems to run ok once you get up to speed. It's fuel injected. Thanks a lot

Answer: Yes a partially plugged fuel filter could be the cause of your problem. And as far as how tough the job is, its like my Dad always said (Bob) "it's just nut's and bolt's... not to bad."

Question: 2000 Ford E150 Van mileage: 140,000. It is now missing, possibility running on 4 cylinders. Fuel filter, fuel pressure regulator, air filter, injectors, distributor have either been replaced or repaired. My question is could the problem be the high-pressure fuel pump. Thanks for your time.

Answer: The fuel pump sounds like it is failing, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 1999 Oldsmobile Cutlass mileage: 135,000. Recently had to replace the Fuel Filter, Plugs. The car was running well until today. Having problem now; it keeps cutting out unless I keep pressure on the accelerator. This seems to happen more when the car is warm rather than cold. It sputters then dies. Sometimes it will sputter when I take a corner or stop at a stop sign, when I remove my foot from the accelerator and then reapply it. On cornering it is like a quick loss of power then acceleration. Does this sound like a possible pump problem or possibly bad fuel? We just filled the tank yesterday.

Answer: The fuel pump sounds like it is failing, check fuel pressure it should be between 55 - 65 psi. If not replace fuel pump with new to recheck system.

Question: 2005 Chevrolet Lumina APV mileage: 61,000. The van acts like someone is inside turning the switch on and off rapidly. When you start it, it idles perfectly, but when you rev it up past about 10,000 rpm's, the rpm's rise and fall between 5,000 - 10,000 rpm's. When you drive it down the road, you only get full power intermittently. It surges until you reach cruising speed, then again as you try to accelerate more, or climb a hill. I have checked the fuel pressure, TPS, MAF, vacuum leaks, EGR, fuel pressure regulator, injectors and all. My next guess is that it is either the cam or crank sensor. But I do not want to buy these until I am pretty sure. Please help.

Answer: Check the ignition coil, sometime when coils short circuit they can cause a cutting out effect. Replace ignition coils with new to recheck system.

Question: 2000 Toyota RAV4 mileage: 100,000. In the morning or after the car has been sitting for a long time initially the car runs very rough, spitting and sputtering along until it runs for a while and then it smoothes out and runs fine. I replaced the fuel filter and spark plugs but those didn't help much. I took the air filter out briefly to see if that was the problem and it still runs rough. Could this be the fuel pump or something else? Any Suggestions?

Answer: You may have a faulty temperature sensor that supplies information to the PCM (computer). Replace with new to recheck system.

Replace Air Filter

Check Engine Light