I've got a ZZP stage 3 S256et kit. I recently started to notice some run-on after i turn off the engine, I threw some fuel system cleaner in the tank just to see if that helps anything. I was referred to a 2 step colder spark plug(.35 gap)...still get the run-on once in a while but now while boosting(apprx. 7psi) i'm throwing a p0300 random/multiple misfire code. I wasn't getting that before. Is the 2 step spark plug too much, and could that be the reason for the misfires during boost?

 

Could be. Try only 1 step colder or even stock.

7 psi isnt that much.

I use NGK 6509 (iridium)

 

well its only 7 right now cause i just changed the wastegate and haven't adjusted yet, it only did it once when i did a pull right after install. i have 6510 in it right now but did find the 6509. I will be switchin to those if it pops up again. appreciate the reply.

 

I tried 1 and 2 step colder NGK's, I couldn't tell any difference, so I went back to 1.
I had misfires at a gap of .035 and I am now gapped at .030 and doing better.

 

.035 is definitely way too big, go .028-.030 and you should be good.