Skip the auto shop - Our mechanics make house calls

Q: misfire on cylinder 4

asked by on

I replaced the coilpack, plugs, wires, o2 sensor, map sensor, egr valve, had compression test Done getting same in all getting spark car starts up fine on first try no problem starting just runs a little rough from the misfire and hesitates on acceleration on hill I've had diagnostics done 3 times no one can figure it out I'm tired of keep paying for no reason and still got same problem service engine light on and rough idle

My car has 168770 miles.
My car has an automatic transmission.

A: You had everything serviced except the one ...

You had everything serviced except the one thing that will fix the problem. The problem is your central sequential fuel injection system has a clogged or defective injector to the number 4 cylinder. Following the manufacture technical service bulletin 00-66-04-00-30 dated Jan. 30 2003. This TSB details a special process to try and clear out the stuck injectors using high pressure of 150psi and then cleaning them with top engine cleaner. If after the cleaning the injectors do not get unclogged then the system will need to be upgraded from CSFI to MFI following the procedures in the technical bulletin. If you end up needing to have the fuel system upgraded, the professionals available through YourMechanic would be able to perform this for you.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: a lot of play in rear axle.

Hi there. The rear end pinion engages with a ring gear and the other end of the pinion is supported on a tapered roller bearing. If there is any radial play in the pinion or axles itself, there is a...

Q: Brake lights don't work when I brake or reverse.

Hello. It sounds like there may be an issue with the brake light wiring system. It is also possible that the brake light switch or brake light switch wiring is faulty. It would be a good idea to have...

Q: Needs to pass smog check..

If the check engine light is only coming on when your on the freeway it might be a problem that the computer is only recognizing at cruising speeds. Your best bet would be to have a certified mechanic read the...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...