HELP strange intermittent problem

[m_ski]

Hi All,

I bought my daughter a 2004 Mustang with a 3.9 V-6 engine. The car has only 22,500 miles on it and is in excellent condition. The problem is that when driving, once in a while, she says it feels like the motor is running on 3 cylinders and has no power. When she presses the gas it sputters when it is doing this. When I drove it right after it happened, all was fine, but the "check engine soon" light was on. It went off before I got it to the shop 2 days later, and they could not pin point the problem. She said it happened again a few days later. I get several thoughts from folks about it but the garage I go to couldn't pinpoint it from the computer message. I would like any feedback from anyone who has had a similar problem. Oh, could a catalytic converter cause such an intermittent problem??

Thanks in advance!

 

[wmburns]

Take it to an autoparts store and have the DTC codes read. Even with no check engine light actually on, the PCM holds "pending" codes.

This could be anything from fouled plugs, to spark plug wiires, dirty MAF, bad CAM sensor. Way too little to go on at this time.

It can't hurt to make sure the fuel filter is clean, the battery is fully charged, and the battery terminals clean and tight.

 

[m_ski]

Thanks for the input

I am not a car guy, (I have a BMW that is serviced @ the dealer...lol), so is my guess that a MAF is an air filter?
Your take on this is right where my other garage guy was going. Plugs, wires, coil etc. I guess we should start going one step at a time with it.
BTW he said the code read "misfire on cylinder 4" which could be caused by any of the above (according to him).

Thanks!

 

[wmburns]

MAF=Mass Air Flow Sensor. It is the sensor just behind the air filter. It's purpose is to read the amount of air entering into the engine. The computer uses this information to compute how much fuel the engine needs.

If you ever decide to clean a MAF for yourself, remember they are easily damaged. Never use anything but cleaner designed for the purpose.

Cylinder 3 and 4 share the same coil pack. One would expect a coil pack problem to affect 3 & 4. However, this is not absolute.

A misfire on a specific cylinder is more likey plugs, plug wires, or moisture in the spark plug well.

Since you are not planning on doing the work yourself, you should let the professional earn his $$.

 

[Aeroman]

Start with plugs & wires, these probably account for 90% of misfire problems with codes on only one cylinder. If not this...... we could be into single injector or compression related problem (probably not compression related since it appears to be intermittent).

Good luck!