So I recently had my cel come on and I had it vaged. The mechanic told me it was high rpm (engine idles at 1100) Last night I was sitting in the drive thru with my car in neutral when all of the sudden the engine starts reving to about 2600 rpm and falling back to 1200. It did this about 4 times and then t he car died and wouldnt start again. We pushed the car and then it started again and ran fine. Whats wrong? My car has 122K on it