I've had my rx8 for 11 months usually never drive it since it uses as much gas as my truck. It has 84k miles in. Manual. Cold starts are fine when I start it on a warm engine it takes about 3 seconds to start. It alwys starts but it struggles. When I drive it for a while the coolant lights comes on for a few seconds and turns off. I thought of switching the sensor which is integrated with the coolant tank. Bought a new one and installed it but I have the same issue. Someone told me that it was the sensor from the coolant that comes from the car not the one from the tank. What do you guys think.

 

https://www.rx8club.com/new-member-f...t-here-202454/


https://www.rx8club.com/series-i-tro...t-here-222584/


Have a read through these threads. The first will get you to understand the car, while the second will give you points to troubleshoot your issue

 

The coolant light runs off the sensor in the tank, the one you replaced. Just to avoid confusion, the coolant light looks like a house with pillars. Is that the light that's turning on?

Read through those threads, particular the compression, ignition coils and hot starts sections.