Both Opera House and Big Dave are correct for what to look at. A bad fan clutch or clogged radiator would cause the temperature to rise. So can a bad head gasket, but with a bad head gasket you will be having to continually feed it antifreeze. A loose lower intake would do it too.
One thing that concerns me is that you are having a fuel ratio mixture issue at the same time. The concern is that water/antifreeze can damage an 02 sensor, so your mixture might be off because the water from a leaky head gasket cooked your 02 sensor.
What I would do. I'd do #1 thru #4 right off the bat and see if it fixes the problem. If not, then I'd do #5 & #6:
1) Check your fan and fan clutch out to make sure it's ok. When the engine is cold, it should turn freely. When the engine is hot, there should be some resistance to turning.
2) Check your radiator to make sure it's not full of crud. Pull the cap off and look at the top of the water jacket. If it's cruddy, you may have a partially blocked radiator. If you suspect it (or if you still have the original radiator in the truck), take it to a radiator shop and have it cooked out. Oh, and go get a new radiator cap. If it's weak, it won't hold pressure and will allow the coolant to boil over and bleed off the antifreeze.
3)Make sure your coolant system is full with a 50/50 mix of antifreeze and water. Not enough coolant can cause similar problems. At this time of year, just having the mix off probably wouldn't cause your symptoms.
4) Check your lower intake manifold bolts.
4) Have a coolant leak down test run. Basically, you pressurize the radiatior and watch a gauge to see if the pressure drops. Any garage can do this cheaply.
5)Pull all the plugs and run a compression test on the motor. All the cylinders should be within about 10% of each other. If possible, do the test with the engine cold first and then again hot. That way a slight leak when the metal expands will show up. Pull all the plugs when you do the test so one cylinder doesn't influence the other.
Just FYI, I know that when I pulled that motor, it had no issues with overheating or fuel/air mix problems. It had never been overheated in it's life. I had never had a single problem with the motor. The only thing that had been done to the motor outside of routine maintenance was an alternator replacement. I didn't check the lower intake manifold bolts, so I don't know if they were loose at the time, but the motor did not show any signs of that problem.
After the wreck, it was throwing a code light, but that was due to the MAF getting oiled up since it sat on it's side for about 2 hours and the oil from the pan leaked everywhere. Once we cleaned that out and reset the codes, the motor ran fine with no codes.
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