Ok so I thought I figured out my misfire problem so I changed the boots, plugs, and injectors ran fine eversince. Drove it to florida and back no problems at all. I take it to raceway park to drag last night and halfway down my first pass it starts misfiring and cutting out at high rpm only (from 5k on) Try to shortshift but still was missing. Needless to say i ran a ****ty 15 due to this . (no its not all my launching as my 60ft was 2 seconds) only thing done are arp headstuds, 255walbro, hks cat back and perrin complete intake. Should I throw in my af gauge and see what its doing at wot. it seems to be the next step?

 

what did you gap your plugs at?? what kind of plugs? maybe your either hitting boost cut or fuel cut, a wideband would help a lot with that. Have your tuner go do a couple datalogs with you to find out whats causing it....id say either plugs or maybe your having a boost leak or a vacuum leak.

 

i had a similar problem. i had a tear in one of my vacuum lines ontop of the intake manifold. I never noticed it until one day i was simply cleaning the throttle body and i noticed a hairline cut in the vacuum line. I put a new line on and it fixed everything.

 

i gapped my plugs at .024 and theyre the IKH22. Im going to check the plugs tomorrow along with a compression test and cylinder leakdown but im 100% certain theyre fine. if everything is fine then im going to have a bung welded to my downpipe sometime this week and put in my wideband. I didnt notice any vacuum lines cut but i guess ill do a vacuum leak tomorrow as well

 

Under the throttle body your EGR lies. More than likely the issue if you don't find anything else. As stated earlier, you have a line off of your intake mani somewhere.

 

look into used spoolin up cop

 

didn't read carefully but did you replace the wires for your spark plugs too if those are going it could be the issue.

 

yes i replaced the wires, boots, and coils along with the plugs at the same time

 

Did you do a boost leak test yet?

 

did not do a boost leak test yet but i did a compression test and found out all the cyl are a good amount below spec. 70 on 123 and 80 on 4. put some oil in and redid 123 barely moved but 4 went up to 145. so basically my "rebuilt motor" is shot