desi

My daily driver, 98 V6 Camaro 5 spd, started to run weird yesterday. It idles fine, run ok under very light acceleration, but is really rough under normal/heavy acceleration.

The engine code is PO306, which is "detected misfire in cylinder 6". What could be the cause for this code? I just bought the car 3 months ago and had been running great until all of a sudden.

I filled up at the gas station a couple of day ago with 87 fuel. Within 5 minutes the car started to run rough. I alway put 89, but this time for some reason I used 87. Later on, I put in Lucas Octane booster thinking maybe it was fuel related. But nothing changed.

What could be possible causes for this code? Spark plugs? Wires? Ignition Module??

I was going to post over on the C4 or C5 side, but I think there's a lot of knowledge on the C3 too

voat

I use to own a 1997 V6 Camaro (I own a 2001 V6 Camaro now, great car with good gas mileage) and there was a problem with the factory plug wires. Just replace the number 6 to see if it helps. They are a bear to change.

desi

Do the plugs/wires have to be changed from under the car? It doesn't look like there's enough room from the top.

In summer, I changed the wires and plugs on my Montana. It took 6 freaking hours. You have to remove motor mounts and tilt engine forward to get to the rear ones... what a PITA.

With this weather, if it's a long job I am thinking it might be better to take it to a mechanic.

voat

I replaced the wires several years ago but from what I remember it was not as hard as your Montana, I did not have to remove the mounts or tilt the engine but I do remember having to get to some from underneath and it did take a few hours, but not six.

Duke94

Not sure if you have the same problem, but I had a 94' Camaro with V8 and 6 speed. Idled great, ran good at low easy going RPM. It would misfire during hard acceleration. Spent many hours trying to figure it out. Even took it to a couple of "experts". After playing with it all summer, I noticed that the plug wires on one side were wrapped around each other. I straightened them out and got the wires back where they should be and no more miss. From what I have been told, the ignition system has MUCH power and will fire the ajoining plug if the wires are not routed correctly. It gave me the misfire code also. I agree with voat, replace the wires. On my Z28, only way was from below.