1989 GMC Sierra 89 chevy TBI

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