I have a 98 Chevy Blazer V6. 235+k on it. Replaces timing chain and gears after it jumped time. Started it, ran with a hard idle. Had it checked out, it was still a tooth out of time. Readjusted the chain. Still runs with a hard idle like it has a misfire in it. Since then, we have replaced the crank shaft sensor, distributor, plugs, wires, and pick up module. Had the head checked, valves a lil burnt but supposedly nothing wrong with them. had the fuel injectors cleaned. It keeps fouling the plug in cylinder 4 or 5. The computer at the store said it has a random misfire but doesn't say where. At a loss, been at this for over 2 weeks.

 

Spiders have been replaced as well.

 

compression test?