I recently changed my engine from a 4.3 to a 5.7. The wiring was the same but the 4.3 had a air pollution system. The 5.7 does not. I didn't seem I had to change the ECM. Cant get the truck up to performance nomatter what I do to it. Is the ECM different between the 4.3 and 5.7? I put a new TPS, IAC, and oxygen sensor on and did not have much of an effect on the performance. Could someone help me out on this? I try my best to do my own vehicles myself cause I cant afford to take it to a shop. Anyone's help would be very much appreciated.