Ok the truck starts up and runs, but it boggs down at high rpms. It shifts good, has good low end power when I'm working the clutch, but I can't coast at a constant speed without losing all throttle response. The only way I can drive the truck is to keep my foot pressed slightly on the clutch pedal at all times. This revs up the motor and allows me to accelerate, but I still can't drive at a constant speed without bogging down.
Does anyone know what this could be? The truck drives the same with either a manual or automatic computer so I ruled that out. My vacuum lines have all been replaced or plugged so I don't think I have any air leaks under the hood. I had to buy a new y pipe and I broke two of the four studs removing the old one. I couldn't drill them out so I bolted up the y pipe with just one stud per side. Also the y-pipe to converter flange studs are missing a nut at the moment. So there's definitely an exhaust leak that must be fixed, but would that cause these symptoms?
The oddest part is that ever since the transmission swap my check engine light wont flash codes anymore. I'm using the same method that's always worked for me...jumping the ecu test circuit with a copper wire and counting how many times the CEL flashes. Sometimes it will flash really fast like it's about to work, but then it never does anything. So I'm unable to check for codes