What Could It Be Now!

[livlifes2short]

Hey I am new to the forums here but am in desperate need of your help. Recently purchased a 94 s10 tahoe balzer 4x4 4.3 vortec (w). The problem is when in park or netrual when I rev it up once it gets to a certain rpm it hesitates or missis. Seems like it wants to fall on its face. Does the same thing in drive I can drive it ok but have to very slowly get to cruising speed. Once at cruising speed or at idle you can feel a very minor miss or hesitation ( not something you would notice unless you were looking for it). So this is what has been replaced so far. Oil, Oil filter, Cap, Rotor, Plugs, Wires, Coil, Pcv, Air filter, Fuel filter, Fuel Pump, Fuel pressure regulator (was leaking spider and nut kit looked good), Cat was hollowed out, and took of egr cleaned and replaced with screened gasket. Please help me here I can not throw any more parts at it, what can I test what should I look at next Thanks And Sorry For The Long Post!!

[Draenor]

Was the spider replaced?

[chevylobo]

dont know if its any help but my parents s10 blazer did the same thing when they hollowed out there cat .there was no back pressure and the thing kept trying to stall we put a new cat on and it was fine .