Hi I have to look help with a friends repair tonight. Its cold and the truck is stuck outside so I am looking to minimize my troubleshooting time. Im told the truck starts easily when cool. Runs about 5-10 minutes then dies. tries to re-start, nothing but cranking motor. Wait two hours and it starts fine for 5 minutes or so. Spark is constant, but there is No fuel spraying once the engine is warm. Once cold the fuel system is fine. no check engine warnings until motor is already dead. With a cheap code tool he thinks he gets an oxygen sensor failure. I know that an O2 sensor will make it run badly, but Should still run correct? I do like the idea of an easy fix however My thoughts so far are: disconnect the o2 sensor, possibly swap map sensor from my truck, use a real code scanner, and hope to figure it quickly. Preferably before the parts stores close or we freeze. Temperature sensor and thermostat should not stop fuel flow correct? Btw he said coolant temperature on dash guage seems to be working normally. Engine is not overheating. Any other suggestions?