HELP - Car stuttering!

[blackf0rk]

I was on my home on the freeway today when I downshifted to pass. The car shifted funny (down, up, down, up) and now the car feels like it's misfiring; I can feel it shaking. The shaking is not random, it's repetitive and with the shaking i hear a repetitive whining/whirring noise. I have no check engine lights on. I have no idea what to do... :help:

[fastblackmerc]

Bad gas???

[blackf0rk]

Could be, I'm on a quarter of a tank and the tank is old. But I dunno - is this really a symptom of bad gas? How do I easily fix this - just fill up again or what should I do?

[Zack]

Plug the fitting from the drivers side valve cover back in.

[Dragcity]

From past experience, a single bad coil can cause this.

I had the coil pack on the passenger nearest the firewall fail on me and had like symptoms....

[blackf0rk]

From past experience, a single bad coil can cause this.

I had the coil pack on the passenger nearest the firewall fail on me and had like symptoms....


Did it throw a check engine light?

[Dragcity]

No, it did not. Tech said it was not "severe" enough. Falt pretty severe to me though.

Kinda felt like two opposing cylinders were failing. The engine shook unbelievably...

Drive it gingerly if at all. Mine straightened out a bit after shutting it down and letting it sit overnight. The next morning it was much better. Tech had to check each coil pack to see which was bad.

[blackf0rk]

Ok, went to the dealer and they wouldn't check the coils because they said they couldn't get any values from the computer since the car was supercharged and the pcm was changed. So they handed me my keys - literally, i was quite upset.

So, does anyone know the procedure for checking the coils? What the ohms should be?

[cyclopsram]

Wait til it throws a code and you can change out the one coil... sometimes they get wet and you will find moisture down the plug hole... Buy a spare cop and you carry it with you....I do that with my CVs..of course I don't have 4 cams and therefore no plate to take off to get at the cops.

[magindat]

I like Zack's answer.

More specifically, check all around the engine bay for an unmetered air path. Intake could be loose. PCV's or their hoses could be loose or off, etc.

[Rider90]

Ok, went to the dealer and they wouldn't check the coils because they said they couldn't get any values from the computer since the car was supercharged and the pcm was changed. So they handed me my keys - literally, i was quite upset.

So, does anyone know the procedure for checking the coils? What the ohms should be?
That's B.S.

If there is a check engine light, great, your answer could be there. It would tell you what cylinder and you're on your way.

First thing I would do is from a stop, put it in drive, hold down the brake like you're doing a burnout, lean into the gas, and listen for a miss. If there is a miss, take the coil covers off and disconnect them one by one. If there is a miss under idle, this will be easy to find. If there is a miss under load only, you will have to disconnect a coil one by one and each time, get in the car and do the same under load procedure. You will find out which one it is when you feel only one miss under load - if you feel two misses under load you will be feeling the coil you disconnected and the misfiring one - so once you did your rounds and you have disconnected one and the miss is the same (one miss only) you've found which one it is. Take the coil out, check the plug, etc.. I have a spare coil around if you want me to mail it out.

Like Zack and others said, check around for the obvious.

If what I said doesn't make sense, look, I'm a detailer okay? :D

[magindat]

...look, I'm a detailer okay? :D
:eek:
Yeah, a detailer who installed his own Trilogy... :bows:

Lotta good advice here. Good luck. :beer:

[blackf0rk]

OK. Update:

I checked all the coils and boots. All numbers checked out AOK. Boots were in fine condition. Pulled all the plugs and they were all fine, gaped correctly.

I replaced the plugs with new ones and now the car is running absolutely smooth!

Only problem now is my keyless wont work?

[Seneca]

I was just wondering.. how many miles are on your car?

[JMan]

Only problem now is my keyless wont work?

Coincidence. Possibly a dead remote battery? I'm assuming you didn't disconnect the car battery when you worked on it.

J

[blackf0rk]

61K now, and I put about 10K on the Trilogy.

Remote is now working. For some reason, it wasn't working right after the spark plug change. But now it's working. And yes, I did disconnect the batter when I was working on it.

[Dragcity]

Black....

Glad everything worked out for you. Nice to hear a success story now and again...