Serpentine(guitarjunkie) conversion belts
 

Well ive just finished my fc build along with the serpentine belts. Now i have a microtech lt8s that is tuned for stock turbo. I do relize the tune will be off, but i dont think it should be THIS bad. In first, the car bucks a little, and will go "pow pow pow pow pow" like its mis-firing. I have noticed, my tps is pretty much all way open according to my laptop at very little throttle. I added .4% fuel on the map, just to be sure of not going lean. And rolled into it, got to about 1 psi, and it got really bad "POP POP POP BANG POP POP!" as it was breaking up and mis-firing at the same time. I didnt reset my timing after installing these belts, do i need to? I am getting tuned by steve on the 28th, should i just have him do the timing and tune at the same time, since i dont know what timing numbers he set it at? Any other ideas?