Truck DIE'S when goin into 3rd
 

I dont know why my truck does this but when i get on it from a stop or a 1st gear roll it feels awsome in 1st and 2nd. Then when it shifts into 3rd it just falls on its face big time. Why is this? Could it be cause the cams or cause i need a stall converter? ? ? ?

Mods are:
Built block
Ported Heads
Crower Cams
Whipple Supercharger at 15lbs boost
Throttle body
Longtubes
catback
Stock tranny

Thanks Johnny

also the truck has twin 255 fuel pumps and 65lbs injectors and a mafia maf

possibly have too much fuel, I'm running 16 lbs on a eaton with the stock injectors and a nice fat tune. Check your tune, running good in 1 and 2 but not in 3 is how I understand it, a converter isssue would be more noticeable from a dead stop unless its locking up too soon. sounds more like a a tune related issue but it could be fuel or electrical related but I doubt it going with your description.

Diadlo or SCT tuning ?Do you have a stall converter?? I think it could be tune related.