extrashaky

Whelp, I may have finally figured this out. Today I finally got around to trying to reindex the cam position sensor. I got everything set and the motor rotated to top dead center, and the toothpick slid right in. So that's not my issue.

HOWEVER, when I did that, the shaft moved. There is a lot of play in the shaft in the center of the oil pump drive that I'm pretty sure isn't supposed to be there, and I also noticed shavings in the head that appear to be chipped from the magnet in the cam position sensor. If that thing is rocking around in there and messing with the cam position sensor signal, that could give me the misfire issue I'm seeing.



I haven't pulled the oil pump shaft out yet, because I want the new one here when I do it. However, I'm wondering: When these things go out like this, do they typically just keep the damage to the shaft, or am I looking at potential damage to my oil pump as well?

cruiser54

Most likely it is limited to dizzy, dizzy gear.
Yank it and see. Look at the cam gear. Oil pump doesn't care as it is driven by a single tang.

extrashaky

To wrap up this thread:

The new oil pump shaft was a lot tighter than the old one. However, installing it had no change. The cylinder 6 misfire came right back.

So the week before last I finally threw in the towel and took it to a shop. After a couple of misdiagnoses from them, they removed the valve cover and discovered that the #6 intake valve spring had broken. I called Chad Golen, and he sent out a set of springs and seals for that cylinder under warranty. It's now back on the road and running smoothly so far.

My big mistake was that I had actually found another thread here where the guy had the same symptoms and found the same cause, but I blocked that out of my head because this motor only has 10K miles on it. I didn't think it was likely, so I never took the valve cover off. If only I had taken that one more step...

cruiser54

Chad is a real stand up guy.