need more info... as to what it could be...

here a few ideas

1. turn up idle needle. usually used to mask problems though

2. when you open fuel tank, it runs lean for a second. your engine may be too
rich LSN

3. when you pit, and you dont clear it, the fuel building up you may flame out. either rev the engine harder at pits or lean the LSN and HSN

to test whether the LSN needs adjusting, let the car sit stationary, count to 5 the car should take off without (or very little) hesistation... do this again, count to 10seconds. the car should take off with a bit of a hesitation and a puff of smoke. your LSN is set.


cheers