Ok, so it seems like a vacuum leak somewhere. But, with brake cleaner and B12, nothing can be found.

Already fixed: intake gaskets, map sensor, sensor on front of intake, new pcv valve, new pcv grommet, valve cover gaskets.

I may try injector O rings next...idk

what else could cause it?

when accelerating, you can feel the misfires, and loss of power, sometimes a LOT of misfiring and backfire...

 

Is it backfiring through the intake or exhaust? If it's backfiring through the intake that usually indicates a spark timing problem that's allowing fuel in the intake to ignite from the spark getting through the open intake valve. Same thing with exhaust, unless unburnt fuel is just igniting from the heat of the exhaust. Start with the basics, check compression, fuel, and spark. Could be as simple as a cracked spark plug or bad wire. Do you have cats? Clogged cats will cause misfires, loss of power, and detonation (that may be confused with a backfire). When tdrumm's GP had bad cats, the car wouldn't go above 4k, started missing, and pinging horribly.

*EDIT* almost forgot to mention, burt valve(s) or valve(s) that aren't closing all of the way can cause spark to enter the intake or exhaust...

 

Well, I just put plugs in it, to see if that fixed it about 500 miles ago, and it didnt, forgot to put plugs. on the list of done things.
Wires are Taylor 10.4mm wires, and fairly new.

The timing was dot to dot when I put the z06 cam in.
Its also got patriot stage 2 LS6 heads, which were just refreshed prior to putting on.

No cats.

Everything was fine, how would a valve get burned if I wasnt running open headers?

 

to small of a valve margin or to far off timing

 

fuel pressure?

 

Could one of your coils be bad?

 

going to check coils next week, im out of town this weekend.
Coils and injectors are next to be checked on the list.

 

when checking vacuum leaks are you looking for a raise in rpm or watching a scope

 

Who tuned your truck?

 

A friend on HPTuners.
He's done many trucks before, so I trust his tune.

Negative, I am looking for a rise in RPMS.
Thats how we found the others.