2015 Chevy spark
About 45 mpg hearing a whiring sound. Have had
breaks checked tires checked and bearings
checked . All looks good . Any ideas?
Could be a transmission problem. Is the transmission shifting into overdrive? On older model GMs the whirring sound would be a system that the transmission lost overdrive and TCC lock in. Do you hear the sound all the time or only when you're at cruising speed? Only at cruising speed would indicate that transmission problem. Hope that helps! Jim