98 Blazer engine response

[Truckedup]

I have a 98 Blazer 4x4 5 spd 4.3 .It seems down on power at part throttle acceleration.It doesn't bog or misfire,just seems like you have to press down on the accelerator more than necessary.Along with this is a slight surging when going through the gears at slower speeds.It idles smoothly,starts well hot or cold.The engine gives good power at wide open throttle once the engine is past 3000 rpm or so. Along with this is what I consider poor fuel mileage for this no options manual tranny 2 door with 3.42 gears.

The vehicle has 120k miles,recently installed new plugs,wires,air filter,fuel filter,cleaned the throttle body and the mass air flow sensor(neither one looked dirty).No codes are stored in the computer.

A mechanic suggested the fuel pressure regulator and or the injection mess inside the intake may need replacement????

[ChevyTech007]

Sounds like clogged catalytic converters. Do an exhaust back pressure test.