Last weekend we noticed that the engine temp was spiking. I still does. Sometimes it’s a matter of just 8 blocks of driving before it’s up, during which the heater doesn’t want to blow hot air. Or, it will have a normal operating temp around town, and then start to spike when we hit the highway, and the heater works fine then (it even seems to take some of the temp off of the engine, like it should.) I took it to Autozone to have them run codes and it came back with a faulty coolant temperature sensor (I don’t remember the CEL code.) I have the replacement sensor and can replace it, but I’m not convinced that this is the problem anymore. Yesterday I had the coolant flushed, but I still have overheating issues. In fact, it seemed to be worse on the ride home from the coolant flush. Anyway, I noticed riding back from Autozone today that it felt like the engine was braking, as if my car were a manual. Now, I’ve ridden a few manuals before, and the braking I felt wasn’t as heavy as the braking you feel when you release the accelerator and the clutch is still engaged, but it’s similar. I think I’m a little overdue for a transmission fluid change. Could that be it? Any thoughts?
My Mazda3 is a 2008 automatic with the smaller engine. It’s stock.