Serial # FGA08-1330-01493. 4389 Hours. It has the GM Vortec G424F engine. I have a forklift that tries to start but backfires loud through the throttle body and dies. It will restart for a couple seconds, then backfires and dies I've replaced the timing belt, gears, tensioner, crank sensor, cam sensor, Ign. coil, head gasket and had the valves ground. I bled the lifters off several times to make sure that the valves are not held open. I've had the head off of several machines with this engine and haven't had any problems. The original complaint was the backfiring, bad enough to destroy the inner air filter. Nothing that I've done has changed it. I found a service manual online for this forklift and got the procedure to find and clear the error codes. It shows no error codes. Is there a way to connect an OBD-II scanner to it? I have an adapter that works on some of the forklifts with the K21 engine. I can't locate a familiar connector. Thanks in advance for any suggestions.