1999 S-10 4.3 V6 stopped running

Truck was running fine and just stopped. Truck cranked fine and ran. About 15 minutes later cranked truck and it went dead. Cranked it back up and it ran fine. Made it about 1/2 mile down road and it went dead. It hasn't cranked since. Replaced fuel pump. Still wouldn't crank. Check ground wire, voltage at fuel pump. Both checked out fine. When I turn switch on to crank, pump runs for a few seconds and then stops. Repeated several times. Then noticed fuel gage wasn't working and "low fuel" light was on. Put 5 gal. of fuel in truck to make sure it had gas (even though my wife assured me she had filed the tank up the day before.) I replaced the relay in the box under the hood. The starter turns over fine just don't seem to be firing. Need help. Wife's truck. You know the saying, "when wife ain't happy, no one is happy".

Spray carb cleaner into the intake, see if it fires, if so you have a fuel delivery problem. Now check fuel pressure, you need around 60#. If it won't start on carb cleaner, check for spark. BTW, welcome to the forum. Of course you replaced the fuel filter?

Sprayed starter fluid as suggested. No help. Would the fuel gage not working (it was working prior to the problem) have anything to do with not firing? Is there some safety device that if the fuel gage wasn't working that would keep it from cranking.

Also the "low fuel" light is on. I know the tank is close to being full. Wife filled it the day before.

If spraying starter fluid in didn't make it fire then your issue is not fuel. You need to start looking for spark.