Newly built engine with 600 miles. Started getting into boost a bit now. It likes to misfire on me a bit... Only when under 5 lbs of boost though. Car runs normal and just replaced the plugs. Never misfires once under vacuum nor less than 5 lbs. I'm nowhere near wot, maybe 1/4 throttle. Afrs are around 12 when it starts to boost and holds. I've been told the boost might be blowing out the spark? Car doesn't sputter or act different when it misfires so it boggles me. Any input is great.

 

Nobody?

 

What plugs and gap?

 

Ngk 1 step colder..035

 

I had to gap .032 for my misfire's to stop

 

im using stock gap on NGK 6509 (iridium) and its .043 gap. 13-15 lbs depending on weather with no issues.