I have a 1996 Honda Civic Cx with 550,000 miles on original engine. The engine is a D16Y7 (1.5). No cel, not burning oil, Manual Trans, original clutch. When car is cold car idles perfectly. When car reaches N.O.T. and cold start system is inactive the engine fluctuates from 1000 to 2500 rpm's (vroom vroom disease) by its self. I am the original owner of the car and it is completely stock. Got any suggestions?