Just a note for the next person. I have a 1994 Camaro Z28 with 212,500 on the original engine and transmission. I had a problem that was very tough to diagnose. The engine RPM would start to surge when the car was warmed up. I would be at a light and all of a sudden the RPM would go up to 1500 RPM or so, if I wasn't paying attention the car would lurch forward. When I scanned I could see the RPM briefly go to 4500RPM on the scanner. After some hours of research I decided it must be the Optispark. The Optispark has about 100,000 miles on it. What I found was the bearing is the Optispark was almost seized. It must have been chattering and causing the high RPM reading. It has been a week and we are optimistic!