stab SOMEONE IN THE FACE! I HAVE TRIED EVERYTHING. Mileage & Performance.

[Anto]

Okay. I'm tired of this 240 miles to the tank crap.

I've searched. Tried everything suggested.

Stock car. 1993 240sx SE with a KA24DE.

New cap and rotor.
New plugs.
Good wires.
New o2 sensor.
New thermostat, water pump and coolant flush.
New PCV valve.
New Fuel Filter.
Injector O-rings replaced.
No apparent fuel leaks.
Coolant temp sensor in resistance spec.
Cleaned IAA/AIV valve cluster via intake line.
Cleaned Air filter & Throttle body.
35 psi tire pressure.
Correct TPS voltage.
Keeping it under 3k 95% of the time.
Timing is at 21*.
Intake resonator removed.
Alignment in spec.
New drive belts adjusted to spec.
Running 0w-30 German Castrol.
Fixed faulty knock sensor harness.
Always run 91 octane Shell or Chevron gas with Lucas UCL.

EGR system seems to be fine.
No vac leaks apparent.

I've gone through each and every single one of these f-ing things. I still get 20-22 mpg.

If anyone has something I haven't covered, please f-ing post it.

Feeling like I want to stab SOMEONE IN THE FACE.

also, when I reverse, during the clutch release, the RPM's drop down considerably, and it stalls out 80% of the time. Even if I gas it a little more than usual, the idle flucuates and wants to die out.
what the f. someone please help me.