Dear Doctor: My 2004 Nissan Pathfinder with 21,000 miles is running fine. Once in a while stopping for traffic or at a light, the engine suddenly starts racing. The last time I looked at the tachometer it had climbed to 3,000 rpm. This lasts about 4 to 5 seconds and returns to normal. My wife is leery about driving this SUV now because she is afraid she may hit someone when the engine starts to race. Have you heard of such incidents? Helmut
Dear Helmut: For the idle to rise up indicates there is a problem that is either computer-related or a lazy idle speed motor. This will cause the idle to rise without setting a trouble fault code. In some rare cases a slow-closing EGR valve can cause the idle to stay high until it closes. Go to a repair shop with a qualified ASE-certified technician. Make sure they work with Identifix for additional troubleshooting.