Im new to fixing my trooper ive had it for 7 years replaced almost everything on it because i love this vehicle, it really is a trooper. single overhead 3.2L 233,000 miles and still runs very well but recently the temp gauge says that its overheating but nothin happens, I can turn on the heater and the temp drops but only if im moving when it idles it starts to rise, i could really use some input any input is much appreciated.

Ever replace the radiator?

Most folks that chase this issue, it ends up with a plugged radiator being the cause.

if you still have the OEM one swap it out.