I have an 89 Jeep Wrangler with a 6 cylinder 2.5 liter engine, manual tranny and no AC, which occasionally will stall out when stopping at a stop sign or when down-shifting while going into a turn. Even when driving on a straight road I’ve found that I can be in 4th gear for instance and at approx. 3,000 rpms and if I push in the clutch and let off the accelerator sometimes the rpms gauge will take a nice smooth ride to about 900 rpm’s and sometimes it’ll drop like a rock, dipping down to 400 or 500 then settling back up to 900 or 1000. In the past year, we’ve put in a new engine, clutch, fuel pump, plugs, wires, cap, and alternator. I’ve had it to 3 different mechanics and had the camshaft sensor replaced, the throttle body cleaned out, the timing checked and the ACI actuator replaced all to no avail. This is supposed to be my daughter’s college car but I don’t feel safe in letter her take it with this ongoing issue which has been happening since we bought the car 5 years ago – before all these changes we made.
You may have a vacuum leak, get a can of spray Throttle body cleaner, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody. Try to keep the spray off the hot exhaust manifolds, it can cause a fire.
November, 30, 2010 AT 5:01 PM
I would have like to think that checking for vacuum leaks would have been one of the first things done - especially at the dealership but who knows? I'll definitely giver it a shot. The dealership wanted to replace the IAC actuator but for $100 labor I figured I could undo three nuts and replace it myself which I did but to no avail. Is the idle air control valve different from the IAC actuator or are we talking about the same part. The part I replaced bolted on to a bracket mounted to the throttle body and had a plug with 3 or 4 wires with a plunger at the other end. Is there any way to test that part to make sure it's working properly?