Once hitting gas pedal, it hesitates to accelerate correctly.
Also having difficulty turning over after putting key into ignition.
RPM gauge will rev up when it shouldn’t; gas gauge unreliable.
Transmission was just rebuilt but didn’t fix the hesitation problem.
Clean the battery posts. Check ground straps for corrosion or looseness. Get the battery and alternator tested. Check fuel pressure.
The gauge problem could be in the instrument cluster.
When was the last time anyone changed the spark plugs?
The first thing I’d do is clean the idle air control valve and the throttle body
Find a place that will put a scan tool on the engine computer, see what it says is wrong. Might as well use that self-diagnostic function. Post the diagnostic trouble codes here for interpretation.
If the vehicle has the 4.3 L Vortec engine, have someone check the fuel pressure.
The fuel pressure should be 63 PSI minimum.
With the gas gauge acting up along with the drivabilty problems the vehicle might need a fuel pump.
Tester