misfire,rough idle

[collinsrc51]

ive got an 06 magnum 2.7 35,000 miles that will miss sometimes at a low rpm but will smooth out at a higher rpm.but it does not miss all the time.it is also showing a p.0.300 multiple misfire code.i have checked one of the plugs and it doesnt look bad.ive heard about some of these cars that would carbon up the valves and do this,anybody got any ideas. thanx

[passnbyu]

Hi, Mine does the same thing. We had it in the shop and they told us it was carbon build up in the valves. I ran fuel injector cleaner thru and it keeps the check engine light out for a couple of weeks but sooner or later it comes back on. I changed the plugs and that didn't help. When I had the intake off (you have to pull it to change the right side plugs) I took a fiber op. camera and looked down the valves. They looked spotless. Even the ports in the heads looked great. No build up. If you find out whats doing this I would like to know.
Thanks Passnbyu

[hundahunta]

normal there is a tsb for this problem...

[spunbearings]

http://www.obd-codes.com/p0300

I'm just curious does anyone have a california emissions car? It should say on a sticker on the top of the radiator support.

[passnbyu]

Hi, What do you mean that tsb is the problem? Thanks passnbyu

[spunbearings]

technical service bulletin

[passnbyu]

Where would I find if there is a technical service bulletin on this. I'm sure more than one owner is having the same problem I'm having. I'm leaning towards the TPS (throttle positioning sensor). It seams to stop when I hit the gas. The check engine light is on most of the time now. Always the same code PO300 multiple cylinder misfire.
Any help will be appreciated!! Passnbyu