I HAVE BEEN RUNNING INTO HIGH HC ON DECEL,ON HIGHER MILEGE GM CARS.

WHAT CAN BE CAUSING THIS PROBLEM,I AM THINKING CARBON ON BACK OF VALVES,TRIED MOTORVAC DOES NOT SEEM TO [...] HIGHER THAN NORMAL HC ON 94 CHEV [...] OTHER GASES ALL NORMAL OR [...] CAT DID N... Login to read more.