I done a track day yesterday and it went really well till right at the end of the day. the car has done 103k miles and after headgasket failure, it was pressureing header tank and mixed the oil and water, when inspected it had gone on number 1. that was all fixed and we went on a track day at brands. we got black flagged due to smoke after over run. came in and temps were good, oil smelt burnt had lost about quater liter, and had gone thin. we noticed a small missfire. each cylinder dropped off as we pulled one plug lead off at a time but it was a definate missfire? got the car back today and