Idle surge

[jeepinwyoming]

Hello all. New to the forum here. I recently bought a 2006 Liberty Sport 6 speed manual. I'm having trouble diagnosing an idling issue. After startup the rpms surge from about 500-1200 every 10-20 seconds. Even while driving there is a surge when I let off of the throttle. I replaced the tps, cleaned the throttle body and all surrounding electrical connections. After a trip to the local auto parts store my alternator reads low voltage regulator failure. I plan on pulling the alternator and having it tested since it is externally regulated. Would this possibly be the cause or is there anything else to check? Also checked for vacuum leaks and came up with none. Any help would be greatly appreciated.

 

[Conundrum2006]

My first guess. Check the Idle Air Control (IAC) it right next to the TPS on the Throttlebody. Unless you have the electric controlled throttle instead of the cable controlled, I know they changed things converting to the electric throttle. Then I'm not sure what it'd be in control of the idle.
Not sure if the alternator is enough to cause this surging.
But it sounds like a classic IAC failure.


Sent from my iPhone using Tapatalk Pro

 

[jeepinwyoming]

Thank you I will check that next. It is cable controlled.

 

[LibertyTC]

Does your throttle body look like this?
58583[/ATTACH]"]

You must be registered for see images attach

If so then refer to this: See Post #10 link: http://www.jeepkj.com/forum/f196/idle-air-control-no-screws-44826/#post475141

 

[jeepinwyoming]

Thanks for the tip about the IAC. Between everything else and cleaning that I believe the problem is solved. I also changed out the spark plugs. They have never been changed. The gap was about .090. I will upload a pic tomorrow of the gap. I'm suprised it never misfired.

 

[J33Pfan]

Thanks for the tip about the IAC. Between everything else and cleaning that I believe the problem is solved. I also changed out the spark plugs. They have never been changed. The gap was about .090. I will upload a pic tomorrow of the gap. I'm suprised it never misfired.

OEM plugs or just copper plugs?

 

[jeepinwyoming]

They are NGK. V-power or something like that. They are a copper plug.