1997 SC2 Ghost Revving

My 98 sc2 did the exact same thing - took about 2 weeks to find out it was a valve that was sticking and needed to be re-placed. i can't remember of hand exactly what valve it was but i was lucky it was covered under warenty. after they 'fixed' it it worked fine.

Turns out it was the coolant temp sensor was dead. I didn't notice until a day later that the coolant temp needle would start at half way, then drop to its lowest point and then back and forth a few times. Brought the car to the dealer and he said the sensor and the housing was completely corroded. Also had the engine mount changed and a loose tie rod replaced. All totalled, $600.00. I now have some new found respect for the dealer. Thanks to the new engine mount, car feels like new when driving. I thought the vibrations I had been experiencing were normal for a car my age!

Frank