Rough idle/will barely idle.

[brianfarm]

Recently had a blown head gasket and ended up replacing the right side cylinder head. At initial start up the engine ran really rough. The code I got was a P0300 random misfire code. I replaced the coils and spark plugs. Still runs rough. I haven’t checked the injectors yet simply because barely ides on its own. So I’m just looking for some help now. Any would be appreciated.

 

[LibertyTC]

Welcome to forums. What year is your Jeep?
The IAC (intake air control) controls the idle and could be carboned up along with the inside port.
See this link: https://www.jeepkj.com/threads/air-intake-control-valve-removal.76958/

 

[duderz7]

I've seen it mentioned that the upstream o2 sensor can cause this kind of problem. I have no first hand experience with that.

 

[brianfarm]

Welcome to forums. What year is your Jeep?
The IAC (intake air control) controls the idle and could be carboned up along with the inside port.
See this link: https://www.jeepkj.com/threads/air-intake-control-valve-removal.76958/

It’s a 2011 liberty sport 2WD.

 

[LibertyTC]

No IAC in a 2011, drive by wire system. Are there any other codes beside the P0300 ??
If you could add 2011 KK Jeep to your signature line, that would be very helpful.

 

[brianfarm]

No IAC in a 2011, drive by wire system. Are there any other codes beside the P0300 ??
If you could add 2011 KK Jeep to your signature line, that would be very helpful.

The P0300 was the only code.

 

[duderz7]

Look for a burnt connection on asd relay under hood.

 

[njpaulkj]

This post is old as hell now, but sounds like timing chain is off a tooth or two. Valve open when it is not supposed to be. Orrrr, the left head dropped a valve seat and is jamming a valve open.