MIssfire under Boost

[Lonnies Performance]

I'll mention a few items that you likely have tried, but...



1. Have you experimented with the plug gap (reducing it sometimes helps) & what gap are you running?
2. Do you have an in-car fuel pressure gauge to verify the pressure is stable under boost?
3. What is your air/fuel ratio?
4. Have you tried to remove the blower belt & remove the intake piping to see if there is a problem at WOT & no boost?

Another item to consider is under boost, the pressure acts against your intake valves offsetting your valve spring pressure.
If you lost some spring pressure over time it can be an issue that causes valve float.