I finally got my GMC starting problem fixed. It turns out my alternator was slowly pooping out. Finally, on a 100 degree day with the AC going, the 40 Chevy quit and would not start with out a Jump. Once running to would generate about 7 amps vs. the 12.7 amp standard but the car ran good enough to drive home. I replaced the 55 amp alternator with a 90 amp version and everything works. My AC, Radio and Radiator Fan additions put extra load on my old alternator and it burned out - I think.
