1998 chevy cavalier loose of power rpms slowly up and down along w/ temp gauge moving in sinq only happen for ten min at a time then back to norm mech said not water pump or thermo
car will go crazy every day or so for about ten minutes then start worlkin fine again . temp gauge goes up and down as rpms go up and down at same time .mechanic said waterpump and thermostat ok . thinks may be ecu ??? Help me please this has been goin on for a week .