car won,t run consistent

:sad: : whats the deal. 1st and 2nd round it runs dead on 7.26@92 mph! leaves hard with no stumble.Thin the third round big stumble and 7.47@88 mph! Forth round big stumble off the line.Mph is back @92 but the et is 7.35.Fifth round same stumble 7.31@92 Mph. the car starts to pick back up but it takes 4 rounds.WHATS THE DEAL :blah5: