Okay, im still having this problem. Things i have tried/checked
Cats dont rattle
Changed Crankshaft pigtail,
Switched to known good MAFs
Ran Truck with Temp Sensor unplugged
Ran Truck with o2 sensors unplugged
Verified i had good fuel pressure
One thing that PT said was peculiar was that my MAF never gets above 0.07 lb/min. But the readings seem to be independent of truck temp.
Thing is that this is temperature dependent but seems to be more time driven dependent. For example, the rev limit decreases as I drive it over time. But one test drive it would limit at 4k and the ECT was 185, then on a really cool day i drove it for 20+ mins and couldn't rev past 3k.
I do have a used camshaft position sensor but from what I understand that would just create a poor start condition. The truck starts/runs great when cold.
On Wed i am going to borrow a Foxwell NT530 scanner but honestly i dont know what to do with it.