My GMC yukon XL 2001 engine runs after 4 times of cranking.

Question edited for clarity, full 'year maker model'.
Question moved to sub category.

There are at least two fuses that mention it.

GMC Yukon (2000 - 2001) - fuse box diagram - Auto Genius

https://www.autogenius.info > gmc-yukon-2000-2001-f... Jan 1, 2017 - The underhood fuse/relay center is located in the rear of the engine compartment near the brake fluid reservoir. ... WARNING: Terminal and harness .

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Low fuel pressure ? What engine ? 4.3 vortec ? Center port fuel injection ? . These are real picky if it does have proper fuel pressure , won't start . These are know for various problems , leaking fuel pressure regulators located under the intake manifold . That is if your yukon has this system ?

What happens if you bring power directly to the starter solenoid? Will it crank then? You need to try to isolate the problem. If it will crank with direct power, the starter is NOT the issue. Let us know what you find.

P0171 is a lean Oxygen Sensor code. It is trying to tell you that your engine is running lean...not getting enough fuel, or getting too much air. That will cause the poor running and dying. This is most likely caused by a bad vacuum leak. The O2 heater code is probably caused by a failed O2 sensor heater. Sometimes it is caused by an open or short in the O2 sensor circuits, but most of the time it is the sensor itself.

does it do this constently

Doubt it. try a code reader. Sound like an emissions problem

it sounds like the fuel pump might have died, or blew fuse or relay see if it gets fuel at the motor

ur idle air control or tps sensor needs inspection-

Have the fuel pressure switch checked.

check coolant level! look for coolant loss