We have a 94 legacy 2.2 with an idling issue.

 

Cold start- On a first start up in the morning it will idle up fine and progressively drop idle as the vehicle warms up. Kosher.

 

Warm start- If I take it to the store or where ever, on the second or subsequent start up, the idle will jump up to 1800-2000 rpms, and will stay there. If you drive the car a bit and come to a stop, if given 20 seconds or so the idle will slowly come back down to normal. It will usually stay down at that point, but not always. Sometimes if given some gas it will get stuck back up there again. If another restart is involved in the trip, it will most likely happen again.

I have been unable to find a similar problem described online. Any help is appreciated. Cheers

Here are some possibilities:

Vacuum leak, perhaps a loose hose to the idle air control valve

Idle air control valve itself may be stuck open.

The engine temp sensor could have failed and the ecu thinks the car is cold therefore holding the IAC open.

 

The IAC is the grey module near the side of the throttle body that has the 1" hose going under the intake tube just behind the airbox.

Is that the same coolant temp sensor that the gauge cluster uses?

I would say coolant temp sensor.

Coolant temp sensor is on the coolant crossover under the intake manifold, not too hard to replace.

Roger that. Thank you

Is that the same coolant temp sensor that the gauge cluster uses?

 

FYI, they are separate, mounted side by side (IIRC.) Try a search on here for ECTS (Engine Coolant Temperature Sensor)--you'll find good info and even pictures.

The proper one for the ecu is the brown clip. The single terminal unit is for the gauge cluster