My98 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??

 

Exacly what the code is saying. Cylinder no 6 is misfiring. Could be a bad plug or plug wire, coil pack going bad, but ulikely astwo cylinders usually misfire in that case, or the injector not working properly. I suspect when you put the cheap gas in cylider 6 may have gone into detonation and killed the spark plug. Put in a new set of plugs & see if it clears the trouble. I am discounting bad gas as in that case you would be getting multiple misfires, code P300.

 

I was just looking at the wires/plugs. Do they have to be replaced from underneath the car? Doesn't look like there's too much room from the top... I am going to pick up a repair manual to see what's involved.

 

Yes. Underneath the car indeed. It will honestly be a lengthy project unless you intend on removing the exhaust manifolds. I was faced with the same problem, and did it painstakingly slow. It's best to have the vehicle as far off the ground as possible. I ended up finding the largest set of ramps I could and using them. Now that I have access to my automotive classes' car lift, I'll be using that for any spark plug related nonsense. The wires, on the other hand, are as easy as it gets, with one man on top feeding you the wires as they're plugged into the coilpacks and you on the bottom plugging them into the plugs.

In short, try the wires first. If the spark plug was faulty, chances are it'd be acting up more times than just during acceleration and heavy loads. When my number 3 went out, you could tell, whether it was at 3,500 RPM or at 900.

 

I changed the coil pack for #6 cylinder and it seems to be running better, but due to weather here I can't really 'push' it. I hope it works out. Changing the plugs/wires seems like a lengthy job.

Thanks for the help guys.