I am heading the salvage yard today for an ECM. I have tested the ditributor, and it seems to be functioning properly. I took it out, hooked it to the battery and then spun it with a drill, while I checked the output of the encoders, and it looks to be functioning. I don't know the specific output specifications, but there was a voltage increase with RPM's on the signal lead, and the injector pulse is coming through strong. It appears to behave properly for an optical encoder.
The problem would be getting it to Autozone to have it checked. I am 40 miles from the nearest Autozone, and 5 miles of driving the Trooper makes the manifold bright red. Personally, I really don't want it to burn, at least not while I am in it. I might call them and see if they can plug it in. I don't know that their machine could tell anything more than having the computer blink codes. From the self diagnostic, the Trooper thinks there is nothing wrong with itself.
I think I have it narrowed to the ECM, but not for sure. I can't think of anything else that would cause it to not advance the timing without at least throwing a code. I would think that if any of the other sensors had a fault that would prevent spark advance, there would be a code for that part. I did have the MAF code, but it has not returned, and the other MAF I got tested exactly the same as mine. Could they both be bad, maybe, but I doubt it.
By the way, the exhaust smells normal at idle, and is rank at higher rpm's. With no spark advance it gets pretty stinking rich above 1200 rpm.