Whenever I run the AC the car overheats, not all the way into the red but close. theres plunty of fluid and its fine without the air on.

My speedo is way off, ill be in 3rd gear at 3000 rpm and the speedo says im going 60mph.

 

sounds like the a/c fan isnt commin on. could be a bad relay or fuse. i would also change the thermostat just to rule that out. and thats pretty cheap and prolly needs to be done anyways.

 

its kinda weird because today it ran fine, no overheating at all.

 

3rd gear 3000RPM, i think that is 60MPH isnt it? or it could be around the 55's, either way i think it should be pretty acurate, you can find out by stopping and seeing if the idle moves the needle