The things that I replaced were either supposed to be, through advice, the source of the issue or already in need or replacement. For example, I replaced the coil after having it tested at 40% spark. I Replaced Cap and Rotor after removing them and discovering they were extremely corroded and eroded. I replaced the fuel injection because when I removed the plenum there was a small leak in one of the poppet lines. Things were done in order from least to most expensive. So, yes, things were diagnosed as I went along...just happens to be that none of them so far are the real original issue.

Moving on. I have replaced the MAP sensor, and the engine is in time. Truck has 293,000 miles on it but motor and tranny are new as of 50,000 Miles ago.
Have not checked exhaust yet.

 

I checked the exhaust for issues and it was all clear. It seems to me as if I have done everything within my power to diagnose the issue. Anybody have more experience or small details that might help solve? The only thing that I haven't looked into is replacing the ECU/ECM. Is that likely to be the issue?