My car has been sounding a little rough when cold on startup and I have had some vibration at 40-60 mph. I figured it might be a bad coil so I bought one and started swapping. I thought I might have guessed right when my idle started at 2300 instead of 1900 or so. I had a wet well, so I tried that one first. No better. The #8 plug didn't look so good when I did the tune-up last week, so I tried that one next and that did it.

I had no check engine light, and it really didn't seem to be a "dead" cylinder. It never missed at idle like my other LS did. It seems that sometimes these coils are "kinda" bad. Strange... When the car was warm and after several miles of driving, it drove perfectly.

I can't take it down the road for a real test, as the front-end is in peices. :(

Just thought I would share, as the symptoms might not be as standard as some of the other posts here.

i never had a rough idle with my bad coils on when under a load did the car perform like it had problematic coils. in regards to teh CEL mine only illumited once, well it flashed for a short period of time, after that I was able to pull a pending code from the pcm that indicated #5 was bad.

I replaced 5 and still had misfires eventually i replaced them all. Best money I spent on the car so far. That and the plugs were well worth the money.

I replaced 5 and still had misfires eventually i replaced them all. Best money I spent on the car so far. That and the plugs were well worth the money.

Are they the same coils as the V8? How much did you pay? I need to see if I can get another one cheap for a backup, before everyone runs out of stock and I am forced to pay the higher price.

I think i paid around 36 37 dollars. I do nto have ther receipt with me. PM mrzeee or email Max at the email address in my signature. Their shipping rates are great so I still saved some serious coin.