Just like the title says. I ran a bottle of sl-1 through and after I ran the whole tank and refueled, I got a p0300 code for random misfire. Coincidence or is this somewhat normal? The car is an 08 impala 3.9 with new plugs and wires 5k ago. No abnormal idle and car runs smooth and fuel eco is normal. I cleared the code and will see if it returns.