Hello, I recently helped my dad do a motor swap on his 88 k2500. The motor taken out was an 88 tbi 350 and it was replaced with a 95 tbi 350. I haven't actually heard the motor in person but he says it has a slight knocking noise when coasting or revving up the engine with no load. If the motor is under load it is smooth and makes no noises. I didnt have much time to look at the ecm data while running but I did notice it was running in open loop. What could be the issue with it knocking. The motor has 180k on it but was driven in another truck for a year before it was pulled and the other truck supposedly ran fine. Will the knock sensor differentiate between detonation and rod knock. If the knock sensor can hear rod knock wouldnt it pull timing and the motor would feel like a dog? The motor seems to have good power all the time.