I recently did a intake manifold gasket on my truck, and have been trying to get the timing right, but a few things are striking me as odd. First off, I have access to a GM Tech 2 with an OBD 1 connector, so I can see what the computer is trying to do to my timing as I drive. Secondly, the timing tab above my harmonic balancer is all scratched up, so I can't tell where 0 degrees is, so I'm guessing at this point. Originally I put it where it's below the 3 smaller bumps, but inbetween the large last bump. When it was set there, at idle my timing was advanced by 20 degrees constantly, and even if I accelerated, it would stay 20 degrees advanced. So I retarded the timing by 5 degrees, or 1 notch on the timing tab. Now its still idling at 20 degrees advanced, but when I accelerate it retards to 2 degrees advanced. I do disconnect the brown with black strip wire under the dash when I time the engine, just in case ya'll wondering. I'm very confused since I know most vehicles will idle at 10 degrees advanced and under acceleration advance to 20 degrees. Since it's staying at 20 degrees advanced, a explanation would be nice, or a way to solve this problem, if it's a problem.