Coupe GT turbo with high idle

[Mark Rutherford]

My 86 Coupe Gt with a MC-1 in it has developed a high idle problem.  It
happened about a 2 weeks ago I pulled the ISV and cleaned it.  Problem gone.
It started to again on Thursday.  I cleaned it this morning and it had no
effect on the idle.

I have did the following

Replaced the ISV with a knowen good one from my 5kcstq.

Check for vacume leaks, did not find any but that does not rule that out.

The temp sensor is good according to SJM site( 130 ohms at full tempature).

Current to the idle stab. is 550 mA with the key on and not running.

Start the car and pull the green wire on the coil it stays at 550 mA should
go to 440 mA according toSJM.

When I unplug the ISV the idle goes to about 750 RPM's.  Suggests no vacume
leak

Checked the idle screw for leaks, seems to be a recurring theam in the
archives.

When I pull the dip stick or open the oil cap there is very little change in
the idle, but if I do it with the ISV unplugged it dies.

Very frustrated
5kcstq at sisna.com