I'll start at the beginning
4 or 5 days ago the check engine light comes on

stays on

Thursday Im driving the car everything seems fine (check engine light still on)

stop to get gas -5 minutes- start car - drive 2 blocks- temp gauge shoots up to red

stop car - put key in "run" position - 2 minutes - needle drops rapidly to halfway point
(not gradually but rapidly)
continue down the road with no problems

somewhere right in here the check engine light goes off

1 hour later stop again -30 minutes- start car and go to back out of slot and needle jumps to red - stop car and put key in run position again - 30 seconds - needle drops to halfway point (rapidly) (check engine light back on, and stays on)

1 hour later same scenario

90 minutes later I get home and park car

let car sit for one hour and check coolant - coolant level good

start car and after about 3 minutes needle jumps to red

once again I turn the car off and place key in run position and 2 minutes later needle returns to halfway point

Now, could it be the thermostat or sensor or what?


(Mileage - 107,500)

 

Could be one or both of those. Get to autozone and have them read the codes on the computer (for free). If it shows thermo is bad, just grab one and replace it. The temp sensor might also show, but since it's fairly expensive, I would just erase the codes, replace thermo, and see if that fixes it.