I was working on my 87 formula. Vin H carberated 305 car today. The car keeps setting O2 too rich or too lean codes. Had the scan tool hooked up and was attempting to adjust the mix. solenoid. Dwell stayed stuck at 45 no matter how it was adjusted. Create lean or rich condition still stuck at 45. Checked O2 reading on scan tool stuck at .82v. New O2 sensor does same as old. Hooked dvom into O2 signal wire voltage is bouncing around just like its suppose to but doesnt show on scan tool.

Now my question is do GM computers use a false reading when they dont receive the proper signal? I know chrysler does and then they show the assumed value on scan tool instead of actual. Or is my computer just toast?

Hate diagnosing computers. They always seem to sting me by not being the problem, and of course you cant return it then.

Any help is appreciated.