Okay, I went and talked to my mechanic again, it appears that the crank-cam correlation value is out of spec. It is stuck at 6 degrees, no matter what he did. Since the vortec V6's have a non-adjustable distributor, it has to fix the correlation in the PCM. The easy solution is to make it adjustable by swapping out the V6 hold-down with a V8 one. I guess I will pull the one off the 283 this weekend.


This is all over the place. Misfire, change everything, problem starts after rarely needed procedure is done, do rarely needed procedure multiple times, and now the problem is claimed to be an issue which won't cause a misfire... not a very methodical approach by any means. It's starting to turn into a drama rather than a helpful thread on fixing the engine.

I've seen cam retard values that are 10 degrees off. The engine runs well and the PCM can still identify a specific cylinder if there's a problem. The only indication of a problem is the check engine light and code 1345. PCM updates cam retard value when engine is first started or when throttle is pressed more than 70% so if that value is off, something is at the heart of it.

My suggestion doesn't change much. Moving the distributor is not likely to be the answer. If there was no problem, then there suddenly was a problem, you should find and fix the root cause. Check the distributor shaft for free play as previously mentioned. Grasp the rotor and try to turn it to check the press fit between distributor plate and shaft. If those two tests don't reveal a failure, forget everything you've been told by the mechanic and start from scratch. Check fuel pressure. Use a spark tester or plug opened up to .070" to check for consistent spark at each cylinder. Force a misfire and ensure the VCM can report the correct cylinder has a problem then check the mechanical condition of that cylinder. I can't stress enough that you're not doing anything besides guessing if you don't follow a methodical approach and when you ask the internet people to make guesses for you they are usually wrong.