It will be something silly and easy to fix. If you don't replace all that stuff it will be the one thing you didn't replace. It's all easy and cheap to start with a good baseline.

You know this is a positive ground system, right? GMC was NOT negative ground. Check that. May or may not affect your tests. So don't get mixed up with the test procedures posted previously.

Please Reread my post, I was typing/editing when you posted again.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn