Thread: Bad Gas Mileage and stumbling idle...again

There's no CEL. I know how to run self-diagnostic but with no CEL I didn't think it would be beneficial. I have 15x8 XXR's on the car, but they are relatively light....wouldn't cause the mileage I'm getting...28 miles on 1/4 tank. Run premium gas...changed the plugs and rotor when I got the car this year, as well as regrounding the MAF

With mpg that bad, I'd check FPR, leaking injector(s), ECT, thermostat stuck open.
Know anyone with an ecu reader, like techtom, nisdatascan, etc.?
It would help to see what the ECU thinks the coolant temps are.
I had a bad ECT once that read 280-300 F on cold start.