I have a 2000 F150 with a V6. Every time I put the truck in gear, the temp needle jumps all the way up then goes back to normal when I take it out of gear. The truck is NOT running hot. There is a check engine light on after it did it but didn't read the code yet. I tried looking this up but had no luck.

 

Nothing ?

 

Since its actually not running hot it could be the gauge itself in the cluster just acting goofy, idk that's pretty weird but check and see what that code is and go from there