still stumped timing or ?
 

1996 gmc/g3500/5.7 tbi still cant get rid of knock, engine idles great but put it in drive and there is no power and the engine starts knocking. Talked to a mechanic and he said there is a crankshaft position sensor on it but I looked the engine over from top to bottom and there isnt one. This engine is in a used ryder truck that the did modifications to, any body got any ideas

Finally figured out that the vin number says its a 96 but actually its a 95 motor, Put a timing light on it and disconnected the brown wire with black stripe, which was at the distributor, and the timing went from 8 degrees advance to 0 degrees advance. But when you increase rpm the timing advances 4-6 degrees, Is this a distributor issue or timing chain, the timing doesnt jump around it stays rock steady just advances a little which would explain why there is no power its advancing to far and causing the engine to knock and lose of power

Don't disconnect anything. Check the vacuum advance at idle, should be around 8*btdc. You should have generally 30* mechanical advance at about 3000 rpm.

The advance on this engine is controlled by the computer, because of all the stuff in the way I cant see how far its actually advancing