There are three versions of the 4.3, the later had the balance shaft. If you have plastic valve covers there is a good chance you have the stronger odd fire engine. Look up what you have. Check your balancer like frscke1 said, remember if the balancer is external balance the outer ring can slip and be out of place and be out of balance. If you have the balance shaft engine, the shaft may have jumped a tooth. GM used nylon gears back then for noise reduction. Back in the 80's many cars went to the boneyard for broken gears at 75k on the clock. The other thing to look for is the balance weight on the flexplate, it is spot welded and can break off. If you have the odd fire engine you may need a timing chain set. Of all the stupid things make sure you're running on all cylinders. Plugs, wires, cap, does 93 have the fuel injector spider? Are you getting fuel to every cylinder? |