engine temp problem?

sorry i know this should b in the problem diagnosis forum and i know this has been covered but i wanted 2 type up my specific problem and see what kind of feedback i could get as to what the problem might be

i drive fine anywhere i go but the last like 6 months my temp gage sits steady at 200 degrees....(195 is the exact middle and mine sits inbetween the exact middle (195) and the first notch....it has never been a real problem for me

now when i sit somewhere and idle or leave my car running it goes up 3 notches above 195 and goes back and forth between 195 and like 235-240....i know the engine temp gauge might be faulty but when idiling my engine drops down 2 700 rpms and then back up 2 1000 in all of about 3 seconds and i just wanted 2 get anyones opinion what it was b4 i took it 2 my machanic

hmm... faulty temp sender maybe? could be a weak water pump... or maybe it's running rich? hell i dunno.

lol thanx for the input