Sending unit truck will turn over but wont crank

I would suspect the problem is the fuel pump. It is located inside the fuel tank. Next time this happens have a spray can of starting fluid with you, spray it into the air intake of the engine and see if it starts right up, if it does you likely need to replace the fuel pump.

This can be a safety feature the manufacturer has implemented in this vehicle. Make sure the oil level is full. Is the vehicle ,making any tapping noises from the top end? ( valve train noise) If oil level is ok, you may have a defective oil pressure switch causing your symptoms. If the engine is abnormaly noisey it is possible there is no oil pressure and further diagnostics will be requred

The crankshaft position sensor is located on the right-side (passenger side) of the engine. At the rear of the engine, behind the starter. You need to remove the starter to remove the crank sensor. Remember to disconnect the battery first. The starter can short against the cross member.

does the starter turn over

fuel pump should only run for about 15 seconds when u first turn the key on now you should check to see if the fuel filter is clogged or your sending unit might be bad on the fuel pump itself

LOW OIL PRESSURE WILL CAUSE OIL PRESSURE SWITCH OR SENDING UNIT TO DISABLE FUEL PUMP.CHECK FOR OIL PRESSURE.REMOVE OIL PRESSURE SENDING UNIT SCREW IN OIL PRESSURE GAUGE TESTER INTO BLOCK WHERE OIL PRESSURE SENDING UNIT GOES TURN ENGINE OVER CHECK FOR OIL PRESSURE SHOULD BE 18 PSI @ 2000 RPM. BESURE TO WRAP TEFLON PLUMBERS TAPE AROUND THREADS TO THE OIL GAUGE PRESSURE TESTER OIL WILL SPRAY EVERY WHERE.IF YOU ARE GETTING NO OIL PRESSURE.YOUR OIL PUMP FAULTY.YOUR ENGINE CRANKSHAFT BEARINGS WORN OUT.WORN DAMAGED CAMSHAFT OIL PUMP DRIVE GEAR OR OIL PUMP DRIVE ROD DAMAGED OR BROKEN. IF OIL PRESSURE OKAY OIL PRESSURE SENDING UNIT IS BAD.

fuel filter may need a change if not done recently

you need to check for power as soom as you turn the key. you loose power afterabout 7 seconds after turning the key to "ACC position". there is a relay in system that shuts off tha power to the pump after about 7 seconds or so. personally I think that you have an issue with the sending unit. xterra has a campaign for sending ubit replacement, because they corrode on the inside of the connection on top where tha connector plugs in under the seat that you took out. This is what you will do: have someone crank the vehicle as you move the 2 wire connector on top of the gas tank. it may start. If not, then take your vin number to the nissan dealer and see if it applies for the sending unit replacement. you may even need new gas tank which is covered under the campaign if its too rotted on top.

yes you should be able to hear the fuel pump run for about 5 seconds once the key is turned to the on pos. check to make sure you have spark. if you do try having someone spray air intake or carb cleaner into intake manifold while you crank. If the truck starts right up for a second (or stays running as you keep spraying) Id say you have a bad fuel pump and id change the sending unit also. (First check the fuel pump fuse and fuel pump relay) GMC and Chevy are nororiously known for having bad fuel pump/sending unit problems. I have prob changed over 60 myself.

Not sure what yor experiencing . Do you have crank no start or no crank no start? No crank no start is battery and cables issue. Crank no start is ignition , plugs, and fuel.