First time on this forum. I've had my 2000 Cav sedan for a couple of years and I'm learning a lot about the car as we both journey together. Lately I've had some concerns with a few things in the car. When I idle the car begins heating up, only until I speed up and force the car to go fast will the thermostat go down. Not sure why that happens maybe some of you can shed some light up on that for me. Also I'm curious about replacing my current instrument cluster with another from a Cav that has a tachometer and I'm wondering if it's just plug and play or will i have to wire some things or swap out the ECM? If any of you can help out with these questions of mine I will appreciate it a ton!