2001 Hyundai Elantra, 76500 miles, runs fine, fluids good, but randomly downshifts from 4th to 3rd on the highway, simultaneous with check engine light illumitaing. Once saw smoke emanating from hood briefly! Could this be entirely the result of an O2 sensor, or maybe a transmission problem?
Jul 17, 2007 at 9:27 PM