Ram 1500 running lean need rich ideas

I have a 98 Dodge Ram 1500 318 4x4 that after running through water runs lean. I have checked and there is no water in the oil/oil in the water. At cold idle it runs like a champ. Once the truck warms up I have the problem of it running way too lean and the truck wants to die out. Once it warms up it starts missing out at idle very bad. It does not have much of a problem as long as i am giving it at least a little gas. As soon as i let off the gas even when under no load it will drop down to about 300 rpms and try to die. Most of the time it will pick back up but there is always a miss at operating temp. When I go to stop is when i have the issues. I I do not think it is the fuel filter since it runs fine at idle and it will rev just fine cold under a load. I have probed the Throttle Position sensor and it is within normal limits. Any suggestions would be very much appreciated...

try replacing the temp sensor