Check Engine Light Issue

[Bluerauder]

Nope -- not on my Marauder. My son has a 2001 Mercury Cougar. His Check Engine light came on about a month ago. He has had it in for dealer service 3 times and it ain't fixed yet. The first time, the service department replaced all plugs and wires. After a few days, the light came back on. Next time, the O2 sensor was replaced. He paid for the part but refused to pay labor. After a few more days, the light came back on. Now the computer code says that there's a misfire in the #6 cylinder and that they'll need to keep it 2 days to work through the problem.

Anybody got any idea of what might be causing this condition so they don't just keep changing parts hoping something might work?

BTW- he's had the gas cap checked out too.

This is very frustrating .......

[Breadfan]

Has the light been on for different reasons each time?

I've got a scanner if you ever want to check it out without dealer assistance

[Bluerauder]

Has the light been on for different reasons each time?

I've got a scanner if you ever want to check it out without dealer assistance

Appreciated the offer Mike. It might be that the #6 plug was not gapped properly during the change.

However, as I understand the diagnostic system in use, it'll keep throwing codes for downstream problems until they work their way back to the original cause. I am just trying to avoid replacing all those intermediate "good" parts while the service department is working their way upstream.

[Breadfan]

Appreciated the offer Mike. It might be that the #6 plug was not gapped properly during the change.

However, as I understand the diagnostic system in use, it'll keep throwing codes for downstream problems until they work their way back to the original cause. I am just trying to avoid replacing all those intermediate "good" parts while the service department is working their way upstream.

Well hopefully the dealer is doing a true diagnostic and not just replacing what parts the code says. Sure a code may say "02 Sensor bad" but to truly diagnose it you must know why the 02 sensor went bad. Sometimes the answer is simple such as it was old or defective, sometimes it's more complex like a rich running motor, etc.

One thing I'd consider doing is if it uses coil packs to swap them around, so the coil pack that runs cylinder #6 move it with another, if the miss moves too it's a bad coil pack.

In terms of diagnostics though I would expect a competent dealer/repair shop to fully analyze the fuel and ignition systems including a live-run diagnostic displaying the full data of the ignition system and by that I mean using a datalogger to map out the electrical pulses going from the ignition system, this will help you id where the miss is occurring and during what conditions.

But I'd say a coil pack swap is an easy check without expensive equipment since they're usually easy to swap around and you could see if hte problem followed the coil pack.

[RoyLPita]

Sometimes wires do go bad. Keep us posted.

[Raudermaster]

It's because it's a FWD V6 Cougar . J/K lol. Wouldn't he have to pay for a new coil pack though to check it on? If I recall, it's just one whole coil pack (3 per side). I know my SHO is like that and if I needed to test it, I'd have to find another one. If the dealer does it, I'm sure they'll charge them for that.

[Drock96Marquis]

Jarod - Yep, just one coil pack for the 01 v6 Cougar, like your SHO



Pull the boot on #6 and see if it's clean and dry inside. Might as well pull the plug and take a look as well.
Check the injector connector for #6 injector as well.


It would be best to get the actual code number - yo ucan go to autozone or similar and they'll scan it for free.

[Bluerauder]

It would be best to get the actual code number - yo ucan go to autozone or similar and they'll scan it for free.

He took the service papers that had the latest diagnostic code on it with him to his new apartment. Can remember it exactly (P0131??) but it did say "misfire in #6). Thanks for the info so far.

[Breadfan]

Are the 2 coil packs on either side interchangeable?

I am probably more used to GM V6's which had 3 coil packs