1989 GMC Sierra 89 Chevy TBI

Engine Performance problem
1989 GMC Sierra V8 Four Wheel Drive Automatic 80;000 miles

When you first start and run the engine it runs fine for about 10 min. Then it goes haywire dumping to much gas into the TBI There is a loud air sound comming out of TBI exhaust gas burnes your eyes very rich, could it be fuel pressure Regulator Or what els can I check.

Thank you Glen