I checked for technical service bulletins and none are indicated for this. Has the check engine light come on when this happens? If so, have you scanned it for trouble codes?
If not, the next thing I would be checking is fuel pressure. Low fuel pressure is more likely to be noticed when the engine is under a load for an extended period of time. If you have't done it, here is a link that explains how it's done.
Also, if you didn't replace the fuel filter, that would be a consideration as well.
Here are the manufacturer's specs for fuel pressure:
1998 Chevy Truck C 1500 Truck 2WD V8-5.7L VIN R
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Specifications Pressure, Vacuum and Temperature Pressure
Open Throttle 66 psi
Let me know what you find.
Friday, January 17th, 2020 AT 10:31 PM