90 3.0 L Won't Idle

All of a sudden an excellent vehicle decided to not idle. Fast idle when cold will keep it running, however slowly, but stalls every time I let off the gas when warm. Also the fast idle won't kick up when A/C is turned on. I know the drill, ISC motor and ECU, don't replace the ECU unless the ISC is changed as well. Is there anything else it could be....without my scanning and checking the ISC motor? I only have 120 K on this otherwise like new vehicle.

Any luck with yours yet ?

I'm in the middle of my "not-running" problem. Saga so far :

Died while running after warming up.
Replaced cap and rotor since I got no spark. (cheap anyways)
SAME PROBLEM - idle while cold then shuts off when warm.

Dealership tested to say that the power resistor was bad. Ordered one ($250) which is the full assembly with coil. Once installed, something shorted it and it fried the brand new power resistor. Dealership ate the cost to warranty and I have a non working truck again.

So I will start the impossible task tomorrow of "find the mystery short"

any suggestions ?

Any luck with yours yet ?

I'm in the middle of my "not-running" problem. Saga so far :

Died while running after warming up.
Replaced cap and rotor since I got no spark. (cheap anyways)
SAME PROBLEM - idle while cold then shuts off when warm.

Dealership tested to say that the power resistor was bad. Ordered one ($250) which is the full assembly with coil. Once installed, something shorted it and it fried the brand new power resistor. Dealership ate the cost to warranty and I have a non working truck again.

So I will start the impossible task tomorrow of "find the mystery short"

any suggestions ?

HAd the same problem with my '95. It ended up being the throttle body servo kit (part# md628059 - $375!) Once installed everything was back to normal.