I have just had my 2wd cosworth re-built - everything.......

its stage 3 as in .. greens, T34 etc ..... it did 3 engine / boost cuts first off, lower down then higher up...... so the map sensor was re-wired and got rid of 2 of them.... so it was then tested with another map sensor which was proven to be Good... it caughed once at 4250 then over the next 4 runs didn't..... So went and bought another map sensor..... now if i toe it 9/10 throttle fine!!!!! BUT when i peddle to the carpet does the cut again at 4250 ish .... almost a boost cut.. then recovers v-quickly and carrys on as normal............ any ideas????????????

HELP

like to add everything is new, leads, dist, coil etc everything