4 Wheel Drive/SUVs: 1996 Chevy Tahoe missing, throttle position sensor, chevy tahoe

Question
96 Chevy Tahoe 5.7.  Misses at regular driving speed but mostly noticeable on inclines.  Also, only sometimes, when starting the vehicle runs very very rough.  One time it did smooth out after driving, the other times we have cut it off and restarted it and it has immediately run fine.  New parts: Fuel pump, fuel regulator, fuel spider, fuel filter, one can of seafoam and one bottle of injector cleaner, intake gasket, distributor cap and rotor button, plugs, wires, cleaned egr and maf.  Has new cat.converters.  When we got this truck the fuel spider was trashed and the intake gasket was blown out on one side, replaced them and the truck appeared to run pretty good but still had an annoying intermittant miss at driving speeds, sometimes it's very noticable and other times it's just enough to barely notice it's there.  I don't know where to start to fix this problem and could use some help if possible.  Vehicle idles at around 5-600 and new fuel pump is running
around 54lbs of pressure (which is the same as the old fuel pump.)

Answer
Wayne,

Run a compression test.  Could be bad rings or bad valves.  Also, run a system scan on the electronics.  May be a faulty sensor (anything from a crank position sensor, throttle position sensor, map sensor or the computer itself), or bad/plugged injectors.

Carl