Hanging idle question??

[asecretfile]

87 GT MAF converted....finally got it running and idles great and revs good on cold starts it revs a tad and then evens itself out like it should.....but once it warms up if I rev it the rev hangs at 1500 rpms for about 3 seconds before returning to normal...sometimes even stalling after a rev. restart easily...this is with the car sitting still. Again this only happens when warm.

the other day I got a code 51

Engine Coolant Temperature Circuit Open

but only got the code once and never again.

Seeing as how this only happens when the engine warms up could I be looking at a bad ECT/ACT sensor since I already have a new IAC valve installed?

thanks

 

[HISSIN50]

Check the ECT signal voltage when the motor is hot (preferably as it acts up). You might also want to do a continuity check in the signal wiring (you'd disco' the EEC's electrical connector and the ECT connector, connect your meter on either end of the return wire. Then wiggle test the wiring harness, waiting for the meter to show high or infinite resistance).

I'd also check for a vac leak - it can cause a hanging idle and/or a stalling situation.