RTW0223

first off here's what i have done...

1992 5.0
gt40 heads
trickflow stage 1 cam
1.6 rr's
trickflow upper & lower intake
255 lph walbro fuelpump
holley adj fuel press regulator
new spark wires/distributor cap & rotor
70mm tb& egr spacer
fenderwell bbk cai


here's what's happening:
when cruising under 3k rpm and i go to step on the throttle there is severe hesitation. it;s like it falls on its face

has anyone with similar setup have this problem? i dont have a tune could it be that? could it be a part mismatch between the bore of the intake and heads?

mattdel

"falling on face" is almost always a very substantial drop in fuel volume/pressure. One of the more common culprits is the baffle in the fuel tank, but even a deadspot in the TPS could cause something similar. If you experience the same problem while taking hard right hand turns and trying to gun it out of the corner, it's likely the tank.
If not, you'll need to find yourself a friend with a nifty scanner and start some data logging.

RTW0223

and to clarify, as there may be a multitude of similar meanings to 'falling on its face', i mean when im driving under 3k rpms and when i push the pedal to the floor, you'll hear the engine rev up as is should, however , the car does not move as it should. the tach will slowly but surely climb upwards. if that all makes sense. lets just say if i were to race from a 40 roll, im sure i would lose to a mini van

mattdel

Ok, that sounds like clogged cats to me. Got the stock h-pipe in there?

RTW0223

no, it has long tubes, o/r h, to original 40s