i have a 2001 F250 gas with the 5.4 that i bought a few days ago it has always ran great and then the other day while sitting in a parking lot I looked down and noticed the check engine light on, the oil pressure and coolant light on and the temp gauge was pegged hot and the oil gauge was down. the truck went into limp mode and I shut it off and jumped out and popped the hood, and it was not hot at all. turned the truck back on and everything returned to normal... stopped by autozone to have the check engine light checked and it was ( cylinder head temp sensor somethine something) I talked to my machanic and he said he was prob the sensor went bad because it would not return to normal temp. i drove it fine for a couple days no problem and not while driving at random times the temp will peg hot again and the oil pressure gauge drops and both oil and coolant light come on but NOT the check engine light. i pull over and check and the engine is not overheating or anything i start the motor back up in less then 30 seconds and it is back to fine.. does this sound like a bad cylinder temp sensor? I also checked the coolant when cold and their is none in the coolant overflow. i just got this truck so havent had time to go over everything. i know that overflow should be to the "fill cold" line when its cold. could that be it?? Thanks alot
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Duh!

Fill the system properly with coolant and burp it properly of air. When an air pocket hits the sensor, the steam is hotter than the coolant so it pegs the sensor's range.

 

as said, fill the coolant tank.
but i don't think that is your problem. i think you have a bad ground somewhere, because it is causing both oil and coolant gauges and lights to act up.

 

Always fill a system from the radiator cap, start the engine and let it run with the cap off until the thermostat opens. You will then need to add a lot more coolant. Then put the cap on and fill the overflow tank. Check it periodically. replace the cap as the springs will get weak over time and/or the seals will leak so it will not suck coolant back in at night as it cools down.