I have a built tranny in my 96 impala with a shift kit. 1st to 2nd shifts really good and firm but sometimes the 2nd to 3rd shift hits rev limiter before it shifts. it doesent slip it still shifts firm but it will hit rev limiter once or twice before shifting.. any ideas on what causes that or how to fix it? the car has never been tuned and it does have a 9" stall