My 95 cutlass supreme (3.1) idles between 2000-2200 when the engine is cold. when the engine temp is about 150 degrees it will idle down to 1200 and stay there. I replace the air temperature sensor and that didn't help. The check engine light doesn't come on if you are driving, but will if l let engine idle.
A few weeks I had to take off the upper air intake manifold and TB to replace a o-ring on the oil pump drive shaft. Does anyone know what sensor might be causing the high idle when cold.