2002 Mountaint 4.0L No Start Issue

I have a 2002 mountaineer (4.0L 145K on the engine)...off and on for the past 5 month occasionally it would not want to start...usually after about 15 minutes it would start. yesterday morning it started up no problem I drove it to the store, shut down, came back out started up no problem drove home parked it. later in the evening went to use it started...ran for a second then died. Wont start now just turns and turns and turns but no fire.
Diagnostics Ive done so far.
sprayed a bit of ether into the air filter to see if she would fire to relate it to a fuel issue---she fired burnt the ether and died.
Checked the Fuel Pump Relay--- relay works.
Checked the inertia switch----was fine.
No CELs on only thing that is on is a "low oil pressure" But when it ran the mechanical gauge read fine. Plenty of oil...just changed it and the filter.
Any Ideas?

Check fuel pressure and injector pulse.

How can you check injector pulse? Scanner>?

Saw some other post...is a crankshaft position sensor still possible?

Use a noid lite. Hopefully your local auto store has one that will work with your vehicle. You can check voltage and ground at the fuel injector.

The symptoms are mostly consistent with a faulty fuel pump. Checking fuel pressure at the fuel rail is a good place to start, as mentioned above. Worst case is you'll find out it has appropriate fuel pressure and you will know you need to look elsewhere.

-Rod