Hi everyone,

I mentioned it to a few people at the last LIOR meeting, but I've been having this issue with my truck for quite some time now. My idle would float around. Sometimes it would idle properly at 600-700rpms, but other times it would idle around 1000-1500rpms, and sometimes as high as 1800rpms. Yesterday I was sitting parked after starting the car, and the idle climbed from 650ish to about 1000rpms in about three minutes. My commute to work today saw my idle between 1000-1500rpms.

I've changed my idle air control motor twice, my intake/exhaust gasket once, installed a new throttle body, and even had my fuel system cleaned and purged. No dice. Someone suggested to me that it could be a crank sensor, and my best friend (who happens to be a mechanic) said it could also be a mass airflow sensor. I've spent so much money trying to troubleshoot this issue to no avail. I'm so frustrated by it that I'm ready to take the car to the dealer to see if they can fix it.

I love my mechanic and all, but I think I need to find a new one, because lately his work has left me unhappy. I'd love to find a guy who specializes in Jeeps too. I've seen a guy in Hicksville who has a sign in his window that says "Jeep specialist" and I've seen LOTS of Jeeps at his shop, but I wanted to know if anybody heard of the place before I bring it. It's Sammy's Auto Repair, on Jerusalem Ave, right under the Hicksville LIRR station.

Anyway, sorry for the wall-o-text. Any help would be greatly appreciated.

Assuming fuel injected, I would guess air/vacuum leak. The O2 sensor would see the lean mix and ask for more fuel, which forces the idle higher. A random/intermittent leak would make the idle hunt like that.

Had the same problem in a V8 Grand Cherokee. Changed the MAP sensor and fixed. I don't know if thats the same as your idle sensor. If you need a shop Try Evan and Mark at Westbury Goodyear. Club members with lots of jeep exp. 516-338-0888

Yes, it is fuel injected. I've been under the assumption that it's a vacuum leak for a long time now because I hear a whistle coming from somewhere under the hood. I've just never been able to pinpoint exactly where it's coming from. I've had issues with the engine running lean before.

Joe, is that the Goodyear place on Old Country Road between Eisenhower and the Source mall? Between Merrick Ave and Merchants Concourse? I'm trying to remember if I met those guys, names are a blur to me.

Bump.

My check engine light FINALLY came on today while I was driving to work. Guess the car finally realized something was wrong after driving like that for a few months. Time to bring it to the shop I suppose.

Buy/borrow a code reader. You could easily have 2 problems, ie the new, unrelated, one threw the code.

You could spend mucho dinero to fix problem #2, and intermittent problem # 1 shows up again the next day.

It would suck to pay to have a loose gas cap diagnosed and then still have the problem.

I can read your codes on Sunday if you want.

I won't be at the trip this weekend Bob, but shoot me an email or something and we may be able to work something out. The codes I've had in the past (that I can remember) are out of control idle and misfire on cylinder 4. I haven't had any misfire codes in a while. I was getting them a lot before I replaced an O2 sensor and my cap/rotor.

Update?

My water pump exploded yesterday, so I brought it to Sammy's in Hicksville. The damn thing was pissing coolant everywhere. I mentioned the floating idle and potential vacuum leak to him, so he said he'll try to check it out today. If not I'm going to have to bring it back another time.

Bump.

So I finally solved the problem. I replaced both crankcase vents (rubber grommets, plastic elbows, and rubber hoses), and the problem vanished. All is good in the world again.