My 1998 mercury Marquis stalls the low fuel light comes on I changed the egr and air control valve.. new fuel filter last year car will keep running if you give it more gas will stall just on idle ??

I answered this already

If a MIL Lamp is flashing please do not use the car

That on a ford that is called a Class A Cylinder misfire & will
destroy your exhaust converter, as well as possible other
engine damage,work on the misfire issues

It could need plugs, or something else. Plugs are designed to last 100,000 miles but no guarantee.
Often times stalling is caused by a dirty throttle body or a faulty idle air control valve. I would have a mechanic check the valve and also see if there are any trouble codes stored in the computer.

The idle air control valve job is to maintain a target idle,

I would check the operation of the idle speed control valve, it is what changes the idle speed when a load like the transmission is put on the engine, without it the engine will idle slow and stall out, this is even more apparent when reverse gear is selected or drive or the AC is tuned on. The ISC valve is located on the side of the throttle body top of upper intake manifold. Below is a picture of the ISC (idle speed control valve)

yes it will remove vaccume line to egr if you can and egr will close if solenoid is attatched to egr then you have to replace egr valve

Drive it to Autozone or Oreillys for a free scan. If your car has a problem causing stalling, you should be getting a "check engine" light. The codes that come from this light will tell the sparkplug that is bad and other things.

I drove a similar car for 165,000 miles and it was going strong when I sold it. While the engine is running take a spray bottle of water and spray around the intake gasket and Airhorn gasket. A bad gasket will change the RPM when water is drawn in. If no luck, sometimes the air chamber under the Airhorn can soot up and as it feeds the EGR passage there can be carbon on the EGR valve. The Airhorn only has 8 bolts and a gasket.

You may find all you need to know with the free scan. Good luck with your car.

P0401- Exhaust Gas Recirculation Flow Insufficient Dectected
Possible causes - Harness or connectors (EGR volume control valve circuit is open or shorted.)
- EGR volume control valve stuck closed
- EGR volume control solenoid valve
- Dead (Weak) battery
- EGR passage clogged
- Exhaust gas leaks Possible solution - Clean EGR Valve
- Repair EGR harness or connector
- Replaced EGR volume control solenoid valve
- Replaced EGR volume control valve
Code P0171- Fuel Injection System Too Lean Bank 1 Possible causes - Intake air leaks
- Front Heated oxygen sensor may be faulty
- Injectors may be faulty
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Mass air flow sensor may be faulty
- Incorrect PCV hose connection Possible solution Dirty air filter of faulty air flow sensor are common causes of the problem P0174- Fuel Injection System Too Lean Bank 2 Possible causes - Intake air leaks
- Front Heated oxygen sensor may be faulty
- Injectors may be faulty
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Mass air flow sensor may be faulty
- Incorrect PCV hose connection Possible solution Dirty air filter of faulty air flow sensor are common causes of the problem.

i would first change the fuel filter with it being run low in fuel it may have picked up some trash off the bottom of the tank so change the fuel filter and see if it runs better

WELL I WOULD CHECK EGR OR IAC VALVE WITCH MEAN IDLE CONTROL VALVE VERY COMON ON FORDS. OR EGR MAY BE STAYING OPEN OR LOOK FOR VACUME LEAK BIG HOSE OR AROUND INTAKE

Bad EGR valve comes to mind here. Assuming the plugs are good, the EGR valve woiuld be what I'd look at.