I have a 2003 ext cab silverado came w/4.8 and now sports a 6.0 stock
now i had a bad tranny and i was racing a guy in a old school mero and the trans flared up when going to 2nd to 3rd and the 6.0 bounced of the rev limiter needless to say it had a slight tap very light i continued to drive it and
it started backfiring when the revs were over 2800 rpm blew the air flow gauge right out of the stock air box eng light is blinking over 2800 so im having a missfire so i pulled the pushrods and there were all straight so im stumped unless i bent a valve or something what do u guys think, thanks
in advance................................Frank

 

Need options before i tear into this thing....

 

let me get it right... you hit the limiter, heard a noise, and now it wont go above 2800 RPM without misfiring??? is the oil pressure right?

 

But the oil pressure is fine i check that but its in the valvetrain. just not
sure where

 

Was the tune adjusted for the 6.0L?

 

But it was just a factory com flash no major tuning but the set up is stock for now

 

that almost sounds like a trans problem... I'd drop the trans and see if it will turn over...

things to do:
drain the oil
look at plugs
looks for leaks/anything unusual
discolored coolant

Just some ideas...

 

As long as you had a stock 6L flash you should have been OK. I was trying to rule out a lean condition if the 6L was running on a 4.8L tune.

 

ive got a timing issue its backfring threw the throttle body and im gettting a check engine light flashing which means a misfire pushrods and rockers are good whats next??

 

I blew a head gasket on a car once and it did the same thing. Ran great until about 3500 rpm then missed and sounded horrible. Might be worth checking....