Ok, I swapped out a 3.1 for a 350 Tpi. When I try to accelerate it stumbles, hesitates, has a light backfire, then goes. However, once its going and I mash it down, it feels like its lacking. It's a .040 over 350, mild ported 083 heads, pro flow valves, lt-4 hotcam, roller tip rockers, 58mm throttle body with ported plenum, and 26 lbs injectors. I'm using the V-6 computer with a moates prom adapter, custom chip (Jet stage2 program with bigger injectors added to the program) and a stock memcal with blank prom(running the moates adapter didn't feel like paying to get the stock prom programed)I'm gonna ground the D3 pin on the ecu because I read it needs to be for v8 applications. Any other ideas. Also I'm getting a code 41 and 43, any hep with those would be great too.