I copped a 1992 chevy caprice with 138k miles from an old white couple for $1500 but the service engine light was on. I know with light being on the chances of passing emissions are low. I know caprices really well and recently changed the spark plugs , wires, distributor cap and rotor. I got the PCV valve replaced and did an oil change. I also added some lucus oil fuel injection cleaner and the engine treatment. The car is riding smooth as hell but the service engine light is still on. I tried resetting the computer by disconnecting the cables from the battery also.