Well, I'm going to bite the bullet and get the timing cover off to see what I can see. I'll keep you posted. Might as well get the opti tested while I'm at it.

 

X3..... The irregularities caused by the incorrect cam/crank relationship are more than enough to throw the crank position sensor duty cycle out of range and cause the codes.

How can the ECM "compensate" for the cam being incorrectly phased to the crank? Maybe in a more modern engine with VVT..... but not in an LT1.

 

If you put a cylinder at top dead. Once the cap is off, you merely check to see that the rotor is pointing in the direction where that cylinders contact inside the cap was. Cylinder 8 happens to be at about the 8 o'clock position. Cyl 4 is near the 9 o'clock position.

I recommend a back cylinder. Checks the state of the cam as well.

 

On one hand I love being right... on the other, I feel like a compleat dumbass for doing that in the first place. Once the timing cover was off it was obvious that it was a tooth off. put it right and put the rest of the car back together (even had the opti tested just for good messure - it came out fine, which didn't surpise me - it's brand new). and the car fires and runs like a champ. No check engine soon lights or anything. Thanks for all your help guys. I always come here first for technical questions.

BTW - Shoebox, half the things I've done I couldn't have done without your website's help, so a double thanks for you.

 

Ya' gotta do stuff to learn...and you learn best by your mistakes. You won't make that one again. Glad you got it fixed up!