Hello Everyone...Finally got the codes that this car is throwing...Symtons of vehicle are as follows...Car has Pinging valves & check engine light is on...Codes are P-1000,P1518 & P-1780...Any help w/this will be greatly appreciated....Mind u the intital problem was it was stumbling and like 1 cyclinder was not firing so we got new wires and new spark plugs I didnt gap the plugs cause the parts guy stated they come pre gapped...if not true what is the gap suppose to be? Mind u after the plugs and new wires car ran fine for 2 days then check engine light came on and valves started pinging..Once again any ans all info or suggestions will be greatly appreciated