I have a 94 Pontiac Bonneville with the northsater V8. This week its been idling fast, 1700 rpm sometimes 2500, most of the time it will idle down after serveral minutes. Sometimes I dont have to touch the accelerator and it will cruise 35mph. Another symptom is in the morning or after sitting for the day (cold starts) it wont idle, I have to feather the throttle for a minute to keep running. Winter temps here are around 15 degrees. I'm sure its a sensor but which one?