full tank OK, half tank and less notOK

[worangejuice]

Hey,
1992 240sx KA24de 5 speed
148,000 miles

Been plagued by my CEL for 8 months or so.
codes: EGR malfunction, fuel injection leak
Checked injectors, EGR valve, all the methods described in FSM, troubleshot everything still CEL and stalls at lights, time to time.
Runs strong, still stalls at lights.
Seafoamed the IAAC and helped for 3 weeks, now it's acting up.

I don't have a fuel pressure regulator 'tool' 'gauge'.
Thinking that this might be it or the 2nd O2 sensor are my hunches
possibly MAF?

When on a full tank or at least half, car is good, anything less then it starts to stall. Also noticed on inclines (parking garage) it will act up .
WOT triggers it as well when I come to a stop.
Just drove to Vegas and back to L.A. Mostly on full or half tank on freeway ran strong to and back, never acted up. Next day home, rough idle, stalling.

Need to re-register so time is of the essence.
Searched through countless threads and all FSM methods.
I took it to a goodyear and they were stumped.
Please help me fight the dealership and their $100 estimate, that may be my last resort,
can't figure this one out for shit.
:cool:

[Anto]

92's are OBD1. There's only one O2 sensor, so scratch that one out.
If your car is running well at a full tank, I don't think it's your MAF.

How are your Injector O rings?
Fuel injection testers are pretty cheap at harbor freight. The price of one there beats paying $100 for a diagnose.

[arkive43]

wrd, sounds like a fuel issue?....mabey ur fuel pump? to me if on an incline and it stalls sounds like ur pump...

[S14DB]

Fuel Pump issue.

[johngriff]

I should be referring you to have me diagnose but...

The fuel pump is submerged when the tank is over half full, this cools the motor of the pump, allowing it to run efficiently.

Since the pump is old, under 1/2 a tank it is overheating and losing efficiency, dropping pressure and volume.

So, replace the fuel pump.

[worangejuice]

Cool thanks, I'll replace that old fuel pump.
*newsbreak*
So I opened the hood and jiggled/pushed back in the plug going into the MAF(has a hole in the rubber, assuming it's old/loose/corroded) and my car idles smooth (awesome!/i'm a dumbass!) and has efficient power like a mofo at all times of day!
I'll pull the ecu when I get a chance and see if it still throws bitch ass codes. I'll also pull the inj. again like suggested.
Oh I love my Silvia, my high maitenance queen.
Seriously I don't mind these probs too much.hehe