87 TBI 350 runs rich, stalls, stumbles, slight backfire out exhaust

[93FatBottom]

I recently did my ECT sensor, MAP sensor, checked for vacuum leaks. Checked fuel injectors and they seem to be working well (no leaks or off spray patterns. Currently have no codes popping. If snap my throttle in park, it will act like its ran out of gas for about two seconds and then rev. If I then quickly let go of the throttle it'll pop (very slight backfire) from the exhaust. Truck never fails to start nor does cranking time fluctuate, so I'm pretty confident it's not fuel related. If I drive it under very light throttle it will stall, especially if I let off. I've read O2 sensors can definitely cause these problems but EGR sounds most likely. I'll probably pick up an EGR from Autozone or Napa today. I may do the O2 as well, but i want to look into upgrading to a heated sensor.

Has anyone experienced similar troubles with their TBI 350?

Thanks guys!