High idle speeds

This 96 SL2 I just got for the kid has another weird quirk. The idle speed
will not come down when you're coming to a stop. It wants to stay up between
1200-1400 rpm. Of course the trans than downshifts a little hard and this is
hard on the brakes. It will stay up at a stop and than settle down to
normal. Next time at stopping it does the same thing. Oddly if you just
"blip" the throttle while in neutral it does not happen. It will settle down
to a normal idle right away.
Ideas?
Larry

 

Vacuum leak, valve body, or TCC.

 

I R&R'd the TB today. Pretty sludged up. Hooked the scanner on it too. DTC's
showed high idle speed (duh?). Anyway after cleaning the TB and clearing the
codes I took it for a drive with the scanner hooked up in co-pilot to
trigger on fault. Nothing So I think I'm out of the woods. The TC seems
to lock and unlock properly and I just put a vb in it for the no reverse
problem.
Larry

 

Sounds like the idle air control solenoid in the throttle body may not be
functioning correctly. This has happened to me and replacing it fixed the
problem.

Lane [ l a n e @ p a i r . c o m ]
"Straights are for fast cars. Turns are for fast drivers."

 

Ran diagnostics a couple times on it and I get a strange code. Reads "PCM
system ram performance" this is followed by Idle speed too high or idle
speed too low or both.
Ideas? I will be looking at the connections to and from the control module
but perhaps someone has seen this before on these little buggers.
Larry