Cooling Probs

I have a 92 Pickup w/ 22R-E

Over the last couple of months the temp gauge in my truck has gone from sitting at the same spot all the time,not matter what I'm doing to wavering up and down.
On the freeway, it sometimes runs cooler than it used to, other times it runs the same as it always has.

In traffic it will sometimes run fine, and other times it will overheat. Today it would get hot mainly when I had to decelerate quickly. Once it was hot, I could get it to cool down some (still was hotter than normal though) by just rolling and revving the engine a bit (2-3k rpms). Once I sped up again, everything was fine. When it did overheat, it would go from normal position (about 11 o'clock) to the edge of red all at once.

I'm stuck on what's failing. I'm thinking the water pump, but I dont have the money to just start replacing stuff until I fix it. I replaced the coolant temp sensor after it acted up the first time, so that is only like 3 months old.

This could be something as simple as a stuck/failing thermostat. Shortly after I got my second toyota pickup (94' dx) the coolent temps started playing a simliar game. Since I bought the truck used in 99' I didn't have a clue about what kinds of maint. the previous owner has done. So I yanked the thermostat since it was the easiest thing to get at and sure enough, it was the one from the factory and was pretty nasty.

I did a test (boiling pot of water) on it and confirmed the problem. Out of 5 tries it only opened a slight bit twice and stayed closed the other times. Quick run to the local autozone and a flushing of the coolent and the truck ran great after that. So give that a check as it's cheap and easy and quick.

Try just pulling the thermostat to see if the temp settles down. Don't play with this thing too much, 'cause most of my failures have been stuck closed, never to open again. If it settles down, replace the 'stat 'cause you don't want to run too cold. As Calimus said, boiling it in an old pan (water) will also tell the tale. Remember that EG is toxic, so use an old pan that you don't cook in, just to be safe.

thermostat and fresh coolant...

99% chance that's all it is

yea try flushing the coolant......and replace the thermostat anyways since the thing is so old. it's only like 15bucks