well before i built my motor with rods and pistons I my tune was smooth all the way from idle to redline. now since it has been built it hesitates right before it goes into boost then its fine in boost. it seems like its loading up with fuel before it goes into boost but it was fine before i built the motor. now since then it has been retarded. any guesses on this?

 

is it tuned? do you have a wideband to see what your AFR is when it bucks? I'm guessing it's eather really rich, really lean or you are having a misfiring problem caused by eather fouled plugs, something in the ingnition system (cap, rotor, wires, etc...) or too much or too little ingnition timing. Get someone to tune your partial throttle maps if you have had WOT tuned already

 

bump because my friend is having a similar problem.

 

Wideband is your friend.