1999 sw2 running rich
 

I have a 99 sw2 that's driving me crazy. Picked it up with a blown engine, rebuilt the motor w/ new everything. started her up today and it ran as expected until it warmed up, then it seemed like it was getting to much fuel (kinda sputtering along at idle). I replaced the temp sensor with a good borg warner brass one, still no luck. If I let it cool down and start it back up it will run fine for the first 5 minutes or so then it goes back to a rough idle like it's getting to much fuel. any suggestions?

Also upon inspection of the iac and throttle body it looks like someone had been tinkering with it before. so I suspect that the problem was there before I got it.

Which temperature unit did you replace, the one for the inlet air, or the one for engine coolant?