11-04-2010, 12:14 AM
its a 90 iroc, 98 trans am block, new ls6 heads, 224 thunder racing cam, 200 shot. I made 5 1/8 mile passes last friday all in the 6.60's. on the last pass she has a nitrous backfire. she has done once before with the old nozzle set up but has been workin flawlessly with the new plate from dave for several bottles. the first one blew the back of intake out. replaced with new ls6 intake. this time it was quite smaller and blew vac caps off and cracked the factory tpi air lid. well i limp it home, 1 hr one way, havin to foot brake it at stops.next morning i cleaned the maf of the char, cked intake for cracks and replaced vacuum caps. runs fine with the idle wanting to float high just for a few secs. im used to that problem but here comes the teaser. i take it for a spin and at wot it hits like a ceiling where it wont rev any higher than 4000 rpm. no matter how long u hold it. it pulls hard all the way to this point then its like the ecu limits it from reving any higher, doesnt stutter or hesitate at all. fuel psi stays at 60, rev limiter still works in neutral, no codes. thought it was a bent throttle blade but it looks fine. any ideas guys?????