I put in a new a/c alt belt and replaced the tensioner pulley assembly. Other than the new belt being a Bondo and maybe a little thicker, it is the right part number. Also, I may have tightened the pulley a shade tighter than b4, certainly not looser. Now, for apparently no other reason, the running temperature idle has changed from 600 to 800. I don't see this as problematic, just don't understand why the change with those minor adjustments. Is there another explanation?

 

that shouldn't raise your idle. do you happen to be running the A/C? running that will raise idle.

if not I would just adjust the screw on the IACV.