my car a 1999 rb5 has developed a slight missfire since being serviced had plugs changed again and it got much better but still there at high revs plugs are ngk gapped to 0.8, car is a std wr sport (ppp) bar being fully de catted running 15 psi of boost i have a new maf fitted as well what is the most likley cause of the fault

 

Try narrowing the gap a bit to .65, have seen this cure high rpm, full boost misfires before. Worth a try!

GlenBec

 

will try but my old plugs which wernt causing a prob were same as ones in car now .8 gap and ngk s