Does this happen to your 4.0?

[90Xjay]

Does this happen to your 4.0?

Once in awhile, when I start it up, the engine revs by itself to about 2700 rpm and stays there for a few seconds, nothing I can do, besides cut the ignition helps. I can lift up on the throttle pedal from underneath and nothing. Its like a hung throttle but only last about 6 seconds. STill not good for just starting and running high revs. It done it about 3 times the other day. I am going to take some good throttle body cleaner and spray and clean all of the carbon out of the throttle bore and plate. I have checked all cables and they are loose and free. I dunno, less mabey I have a ICS (idle control speed) motor or TPS Throttle position sensor, but usually they cause the motor to not idle high enough, and I have no check lights on either. I was thinking about posting this elsewhere also cause this is not just an XJ issue, it has more to do with the injected 4.0

Thanks

90

 

[jeepmaster]

RE: XJ passenger window

if its carb'd it might idle a little higher when its cold. mine will run 500-1000 RPM's higher than normal at startup randomly but its doesnt happen very often. its latest trick is to refuse to start right after i get gas. no cranking, nothing. the radio and stuff works and it only happens sometimes after i get gas. i guess its a jeep thing

 

[88Wrangles]

RE: Re: RE: Re: RE: Re: RE: Re: RE: Re: for robrt-stephens

My mom's Mercede's started doing that a couple weeks ago, and it's fuel injected. I'd also like to know what might cause something like that. Right now the car just sits cause she bought a new one yesterday....but I still need to get it to stop doing that (for selling purposes).

 

[jeepcherokee]

RE: Re: RE: Re: RE: Re: RE: Re: RE: Re: for robrt-stephens

I really don't know if this will help, but i have drained my battery 2 now. (yes i am an idiot) and both times when i was boosted the engine reved to about 4000 then dropped to 2500 for about 10 seconds right after start up. It scared the poop out of me the first time, but i was assured by the tow truck driver(i thiought i was going to have to have my ignition replaced okay) that it was common for this to happen. So what i am saying is that maybe you got some power gremlins??????????

 

[Bounty__Hunter]

RE: Re: Suggestions...

The '90 is injected, and it's likely in the sensor on the throttle body that controls idle. You should notice a difference after cleaning the TB well.

 

[88Wrangles]

well I'll give that a try Bounty and see if that brings that little problem to a stop. Thanks!!