a.dickens

I started my 88 xj this morning and as soon as I cranked the key, the RPM's jumped to about 3k and held steady. I put it into reverse and the jeep shot backwards staying at 3k rpms. In neutral, the RPM's go up to about 5k and hold steady at 5k. In drive with my foot smashed on the brake, they will hold at 3k RPM and the truck will hold there but as soon as I let off the brake, it will go like I am accelerating. When driving, the RPM's are pretty normal and when I am in 3rd gear, they will drop to 1500.

I dealt with this on my 5 mile drive to work this morning and noticed no other issues. Engine temps were normal and oil pressure was normal. Once I parked I got out and there was coolant leading from the front (radiator/heater core area) and from the coolant reservoir. The coolant had splattered all around the engine bay and was leaking down to the ground.

Are these two things connected? Would a stuck accelerator cause the coolant to leak? My guess is that the accelerator being stuck caused the engine cooling system to work extra hard to keep the engine cool. Sitting at a red light for 2 minutes while holding 3k rpms doesn't sound like a good thing for an engine.

Any suggestions on what to try first to get this fixed?

TrekkerJmm

I would check/replace the TPS (throttle position sensor) If it gets wet it messes up the idle and throttle. I would replace it and work from there...Tj

fantic238

Leave the TPS where it is. Replace the IAC instead. The tranny fluid lines in the radiator overheated the cooling system.

greenjeep23

Did you park next to toyota or something? Nah, try and change the iac. It sounds like it could be that.

a.dickens

I recently seafoamed the engine through the throttle body, revved it a while, drove it about 45 minutes and then it sat for a day. Would that give more info that helps diagnose the IAC? Might it be dirty from having whatever was cleaned out during the seafoaming gunk up the IAC and then cause those odd circumstances?

I just went out to the parking lot and cranked it up and it idled very low, lower than normal and certainly MUCH lower than the 3000 rpm it was idling at. Good sign?

Thanks as well to everyone who has pitched in so far. This is one of the best forums on the net with some awesome people.

Ogre in KS

GreenJeep beat me to it, I was gonna try to think up something clever to say about the Prius,lol. I don't have a clue about your high rev problem, good luck getting it fixed though bud

fantic238

Electronics+chemical solvents=no good.

a.dickens

Update: After work, I cranked the xj up and drove home from work. For about a minute, everything was normal, but after that the idle kicked up again and it was idling at 2k rpm. I drove it home and when I got there, it wasn't leaking any coolant so that made me feel a lot better. I pulled the IAC and the bronze tip was solid black. I used a toothbrush to clean the carbon buildup off, reinstalled it, and it runs perfectly. I went for a 20 minute drive and it didn't act up at all.

Thanks for your help