I have a 94 6speed with a 383ci LT1- CC306 Stock heads with 2.02 and 1.60s
255wal with 42lb injectors

I have been having weird problem. The last 2 time I have taken it to the local drag strip during play days.. IT runs like crap!!

At first it would pull hard during 1st and 2nd and fall flat on its face during 3 and 4th. Even while doing the burnout it would die out sometimes.

Got the car tuned a little bit.. Pulls alot harder in 1 and 2 and the night before the last drag race even in 3rd and 4th was doing alot better.

Now when i got to the track the car got back to doing the 3rd and 4th face on its face thing. My dad is a mechanic and tracked down the fact the gas cap was not vented.. Ran alot better but still in 3rd and 4th it feels like there is more left in it..

Still need more tuning you think? any one ever have problem like this?

ps.. hope i posted this in the right area!

 

Got tuned a little bit?

What does that mean?

 

Have you checked the fuel pressure? Are you running a stock fuel system (tank, vent system, lines, fuel pressure regulator)? If so, its designed to operate with an unvented cap. I'm pulling 800HP on a stock tank with dual pumps, using the stock unvented cap and never had a problem. That assumes you either still have a functional EVAP canister, or have deleted it and kept the vent line functional.

Have you checked for misfires?

"runs like crap" and "falls on its face" are vague statements. Describe EXACTLY what happens when you shift into 3rd. Does it start to misfire, stay smooth with a general loss of power, shut off intermittently, etc. What does it do when it "dies" during the burnout - just shut down, lose power, misfire, etc.?

Have you ever done a diagnostic scan/data log?

Normally this sort of post belongs on "LT1 Based Engine Tech". It makes it harder to keep it here on Advanced Tech with the crude descriptions you are using.