Re: Any TBI knowledge out there
Easiest way to see if it's the EGR valve - disconnect the vacuum to it. If it's electronic with no vacuum, plug the plug into another one so the computer "thinks" it's still there.
Your symptoms indicate fuel starvation - low pressure at WOT. Filter, weak pump, crimped line etc.
Easy way to check that is with the propane trick. Use a propane torch, take out/drill out the restrictor orfice, take off the torch head - you really just want the valve. Slip a long hose over the tube - tie the hose end into the airstream, take the bottle inside the truck with you.
Hold the bottle upside down in your lap (to get liquid rather than gas.) Run it to where it's starving, open the valve. If it "likes it," it was fuel.
Propane will burn very similar to gasoline - adding it under load is about the same as pouring in a little extra gas -- but far safer. If the engine was starving for fuel, it'll "like" it.
Some folks seem to think it'll make the engine run lean and be harmful like nitrous - but propane is fuel, not oxygen.
Good for finding vacuum leaks too.
A small vacuum leak will not cause your symptoms.
Could be a weak ignition too, look there if propane doesn't help.
Let us know what you find please - it's frustrating to never hear what worked.