I heard something about the jdm motors running lean when using a usdm ecu, and lately I think my car is running lean. A few people told me that if the car makes popping sounds in the exhaust while idling that is because its running to lean. Yet the temp guage has not moved. I have got some of the best mileage on this last tank could it be a fuel pump thats dying or something else? Thanks for any advice.