Chris,

Warm the engine, shut it off. Disconnect the  clip at the end of the
idle stabilizer valve - that cylindrical thing right on to p of the
engine with the clip and wire on the end. Remove that clip, restart the
engine, check the idle. If your engine smooths out and idles steadily,
your Idle Stabilizer circuit has a fault. Could be the valve on top of
the engine or the box behind the right hand tail light. All this is
dependent on the Temp sensors working correctly. It the Temp sensors
have a fault, then this little ISV test may not be accurate.

Regards.

John Rodgers
88 GL Driver
Chris Snyder wrote:
> Hello List,
>
> OK, I have gone over the engine with a fine tooth comb looking for vacuum
> leaks broken wires, etc. I can fine nothing wrong.
>
> I did notice that the thing in the middle of the engine with a plastic pipe
> going to the AFM snorkel is not "Humming" would this cause a high idle when the
> engine is warmed up? I believe the part is my Idle control sensor. I don't
> want to replace it until I am dead sure it'needs to be as the part is pricey.
> How do I check it?
>
> The only other thing I can think of is the Idle control unit and here again
> it is an expensive part as far as sensor's go. How do I check this out?
>
> What other things would make my idle go from 800 cold engine to 1,500 when
> it's warmed up in neutral?
>
> The van is a 1987 with auto tranny.
>
> It didn't do this high idle until I replaced the coolant thermostat the other
> day.
>
> It does not seem to make any difference weather any asscories like the A/C is
> on.
>
> Hope someone can point me in the right direction. Other wise I am going to
> spend about $500 for the idle sensor and the control unit without knowing if
> they are my problem for sure or not.
>
> again, thank you to everyone for your help on this problem.
>
> Chris S.   </HTML>
>
>
>