MIL - code P306

The MIL came on on my wife's 05 Pacifica. I took it to autozone for their free scan. I have the factory repair manual and it says it's a misfire on cylinder #6. So I replaced the plug (the old one was not in good shape), cleared the code, but after the "reset" phase the MIL came back on, same code. This time I replaced the ignition coil, reset the code again, but it came back on the next day. It also will not rev above 3000 rpm when not in gear (will start sputtering), but when in gear, even under load and going up a steep hill, it has no problem keeping it running smooth at 3000 rpm and going beyond. Now, when the engine is cold, it idles rough, and it accelerates rough as well, but once warmed up, all seems fine. I checked the K&N filter, which I put in about 10 months ago when we first got the car. I also ran fuel injector cleaner through the last tank. I am stumped at this point. MPG is in the normal range when warm. Does anyone have any suggestions what else to check for?

BTW, it was not easy identifying cyl #6 either. I think it's the one on the firewall side closest to the air filter. The factory manual shows the schematic based on the 300C engine, indicating the "front" of the vehicle where we would have one or the other side. Perhaps I identified the wrong cylinder?

Thanks,

Andreas

Number 6 cylinder is the one closest to the firewall on the drivers side I believe.
There is a service bulletin for 05 Pacificas. It has to do with rough idleing and multiple misfires. It deals with carbon build up on the exhaust valves. Below is the basic info for it. You could take this to your local Chrysler service center and ask them about it, and see if this is a possible fix. Hope is help a little.

2005 Chrysler Pacifica
Bulletin #:0900505 Sequence #:10018981 Date:09/16/2006 Component Name:061000 engine and engine cooling:engine Make:Chrysler Model:Pacifica Year:2005 Summary:Multiple cylinder misfire or rough idle. *tt