TJ03f150

can a misfire cause boost spike?

i thought my boost controller was failing until i replaced my coil pack due to a small misfire at idle.

after replacing the coil pack the truck idles 100x better and now i realized that i actually had a misfire while driving, i just couldnt hear it, i thought it was just a bouncy road... it would feel that way at about 40-50mph.

before the coil pack my boost was spiking from 7-10 on up to 11 and then holding at 7.

2 days ago i replaced the coil pack and now it holds boost at WOT very well! atleast i think it does i dont know for sure yet ive only gone WOT once (today) and havent been wot for about a month because I thought my boost controller was causing the spike.

so to sum this up...

can a misfire cause boost to spike? if not spike can it cause boost levels to fluctuate?

oiN8io

I would think it could cause fluctuation in boost levels, but a spike i dunno?? maybe.. you should get out there and try a few more WOT pulls to see if you problem is fixed..

TJ03f150

problem is fixed! i did more WOT but im kinda worried about my tune, ive had a misfire for so long

i guess as long as my A/F's read okay then i should be fine.

and my a/fs are great at wot, 11.4-11.8!!!

unfortunately i still have a misfire at idle and it seems to be when my a/f's bounce around from 14.5-15.2, im going to go with thicker spark plug wires and change the gap down to 34 from 35 and see if that helps. may even replace the o2 sensors in the headers...