Your truck doesn't have a MAF. Since it'* a stock TBI, it has a MAP sensor.
If you want to eliminate the EGR has the problem, try unhooking it at the throttle body and plug that port on the throttle body. If it still doing the same, then it'* not the EGR.
I'm thinking the MAP sensor could be the problem. Try unplugging the 3 wire plug at the MAP sensor and then try running the truck. If it solves your problem, then it'* either the MAP sensor or one of the 3 wires going from the MAP sensor to the computer is bad. I've seen one of the wire going to the MAP sensor go bad before, one on a 95 Silverado and my 92 Caddy. Both vehicles ran so rich, it would kill the motor.
That'* my 2 cents.
*2005 Vette LS2 103k DD
*1980 2 door Pontiac Bonneville Olds. 350 Diesel 198k *1991 Pontiac Firebird ??? 195k *1987 Chevy V10 Silverado Chevy 350 HSR 230k *1993 G20 350 TBI 252k