Start by checking for error codes on the ecu. This is done by bridging the TE1 and E1 terminals in the diagnostic box. google will tell you how to read the codes, and if you haven't hooked up your Check engine light, now is the time to do it.
Also worth getting your exhaust mated up as open headers can also cause it to cut out under load.
well its goin for exhaust tomorrow morning, see how it goes. only does it now when the car is stopped. when im driving it, it doesnt happen at all.