fixitman

gotcha, i apologize for the persistence of the matter but as long as i got you here and fired up, i have a question about my jeep, there is a problem with my idle, at first it idles just fine at about 800rpm but when i let it sit and idle for anything over a half an hour then it starts to misfire, more and more the longer it idles over a half an hour, and eventually at about 45 minutes of idleing it goes into limp mode where there is no power at all and it sputters until i really get on it hard and bring it back into regular running order, now ive checked my codes and they said rear o2 sensor i replaced both and i got no check engine ligth and never have but it still does it, what do you think is the problem? i have 156k miles and it just started happening at about 150k miles
thanks

okcjeeper

well things that could affect the idle that I would check are IAC and maybe MAP sensors. Does the jeep heat up beyond 210?

Moved this to it's own thread so you get more eyes on it..

fixitman

no it stays at 210, i havent checked either of those sensors. i figured they would throw a code and the cel light if they where bad but how would i check them to see if they are?

fixitman

https://www.cherokeeforum.com/f2/idle-problem-11549/

farmfuel

Yea, I was gonna ask what the temperature gauge is doing. Temp sending units going out can make computers do weird things.

Perhaps your fuel pump is getting hot? With 156K miles...have you ever changed your pump out? Maybe you should hook a fuel pressure gauge up to your fuel rail, and monitor the psi while parked, and while driving.