1994 Ford 5.8liter engine. Ocassionally you will stop at stop light and the engine is idling real high. Once it gets in that mode it stays until you shut off engine and restart. Today I ran around as if I had an egg under my throttle foot and the van run fine all day. This was an attempt to NOT actuate the EGR. The engine error codes are: 332 EGR, 311 Thermactor , 411 rpm not in range, and 412 can not raise rpm.