Recently bought a 93 short bed with 4.3/automatic tranny, mainly for rust free body it had. Started and ran, but acted like maybe catalytic converter was plugged. Replaced that, then fuel filter, then fuel pump. Still no pulling power. Finally checked timing. It was off almost ten degrees. Now runs like new. Thought that might help others with similar problems.

 

Thanks for posting the fix. I'm sure someone will appreciate this help at some point when working on their truck.