Hello and I hope someone can give me some information on what's going on with my car.

I have a 91 Firebird 3.1L. this all started at the same time. I have a very high idle 1500-2000 rpm, fan won't come on, and won't shift into OD at highway speeds. If I disconnect the coolant sensor by the thermostat it will shift ok, lower the idle and the fan will stay on. I just redid the entire upper intake and don't believe that I have an air leak that could cause all of this to happen. Can anyone point me in the right direction?

 

Are you getting any engine codes?? From your description there is a possibility that the temp sensor is suspect (if you are referring to the temp sensor and not the temp gauge sending unit). I suggest this because when cold, the computer "Sees" the coolant temp via this sensor and idles the engine higher until warm. It will also not allow shifting into OD until the engine is warm. I had this on my Mazda a while back and same symptoms.

Can you give any more info??