1997 Pontiac Grand Prix Stalling

I have a 1997 Pontiac Grand Prix, that stalls out while driving. It does not matter if you are driving at highway speed or residential neighborhood speed, it will stall. Serveral things have been replaced that has been known to cause this problem, but still no fix.

The car first showed a hard code for the mass air flow sensor.(Only code that has ever shown up). When removing the old mass air flow sensor, it practically fell out, broken at the soder joints. Cool, Fixed? No.

Checked fuel pressure, even when stalls, no drop in fuel pressure.

Swapped out ECM, no fix.

Was advised by mechanic to replace Cam sensor, and crank sensor, replaced. Still not fixed.

Checked ground on transmission, ok.

Car also had blower fan, headlight, rear defroster issue. If you turned up (past 1st notch) the blower fan, the headlights would cut out and rear defroster would not work. Found by replacing ingnition switch, solved this problem, still stalls.

Tried replacing ignition module. Still stalls.

Removed idle air contol valve, cleaned, replaced. No fix.

Finally take it to pontiac dealer for diagnosis,
Was told needed fuel pump, they got to drop pressure. Replaced fuel pump assembly (in tank) drove for 2 days, fine, stated stalling again.

So I am looking at this point were to go from here. Any ideas would be greatly appreciated. I am left scratching my head at this point.

Thanks
Scott