High Idle Issue

[96'er]

I just completed a KS and hose replacement on my '96 Q and after all that is said and done, the car now idles at 1000-1100 rpms - fully warmed. There is sufficient slack in the throttle cables.

On start-up the car jumps to 2K then drops to 1.5K and then to 1.0-1.1K rpms all within a couple of seconds. The engine doesn't hiccup at this idle speed nor run rough. The car drives fine around town.

I had the Auto Zone hook-up their ODBII to clear the KS code and re-check the car and no codes where thrown, so I am scratching my head on this one.

Any ideas???

[elwesso]

small vacuum leak. If memory serves on the 96 you cant adjust the IAC (good thing).

recheck your vacuum lines on the back of the plenum, mainly around the EGR and the line that goes from the plenum to the FPR. Also be sure all of the plenum gaskets are seated properly.

[96'er]

Ugh! Well at least I know how to take it apart and things will go much faster

[qship96]

If you cleaned your plenum and throttle body and AAc valve during disassembly,might just need to reset base idle....someone in the past may have cranked it up to compensate for dirty intake path that no longer exists,which now shows up as too fast an idle.Idle set screw is on pass. side of AAc valve.

[elwesso]

OH ok, I thought the IAC was NOT adjustable on the 96s.. if it idles smooth, reset the base idle... Turn the screw in all the way in and screw it out about 2 turns, thats where you should be.. if its still way high, then check elsewhere.

I had that on my Q. I did everything and it finally turned out to be the IAC was just set too high.

[96'er]

I did clean out the plenum and TB when I disassembled. I checked out the IAC valve and it looked clean, the needle looked a little dirty but the inside of the valve body was not varnished like the plenum and TB.

I presume the adjustment is on the passenger side of the engine compartment and adjustment should be made after the vehicle has warmed up.

Is there anything I need to pay attention to if I want to clean the IAC valve?

Thanks.

[silverQ]

Hmmm sounds like what I did .. is it cold outside? When I replaced a few injectors I pinched one of the coolant hoses feeding the throttle body and fast idle cam. Making the fast idle cam stay engaged all the time. That's probably whats wrong ..

[Woot!]

Mine did this same thing when I lifted the plenum up to fix the fuel leak under it. Is what the problem was was one of the plenum seals weren't aligned and it was causing a vacuum leak.

The first thing I would do is check the seals on the plenum. It is very very easy for one of them to not be aligned.