NEED HELP? missfire

[dunehopper502]

i have a hard miss when acclerating,happens about 3800-4200rpm then clears up and will rev out fine...any suggestions?


this is what i have 90 k5,98 (r)motor vortec with gmpp intake,mild cam,gm roller rockers,msd distributor/coil//6a box/,tbichip programmed for motor,high pressure pump,afpr in tbi,

ive checked timing 0* with est disconnected,replaced map and tps sensor,replaced dist with stock unit,disconnected msd box,newplugs,wirez,ecm,still does it im running out of ideas,the motor was fairly new when i got it and had it gone through and inspected when had cam installed......any suggestions on what to check or do next?

carbed bigblock is looking better and better

 

[dyeager535]

You hitting the knock sensor?

Who did the chip?

 

[Thunder]

have 1 question. How much fuel pressure are you runing?

 

[dunehopper502]

new knock sensor and checked wiring to it,looks ok...also brian at tbichips made the prom

and for the fuel pressure i need to get an adapter to hook up the fuel pressure gauge,smells pretty fumey so i assume its rich

 

[dunehopper502]

figured it out,quality gm plastic intake gaskets sucking air and giving me a lean miss...nver of thought to check due to being brand new and only a couple thousand miles on it if that

used fel-pro gaskets which are all steel with a silicone overlay very nice