Report "I have a 1988 Chev truck with 4.3 l V6 4X4 with AC, the engine was just rebuilt complete. After completion the engine idles fine and start good. no error codes are found when performing checks. Fuel presure is good. Problem: when test driving the engine will not accelerate, seam as if the timming is off, but base timing has been checked and verified. Looking for suggestion to correct"