Mercruiser
New member
I’ve got a 2015 Sonic, roughly 66,000 miles and within the last week it has been idling really rough and stops, stop lights, etc. No check engine light on and it runs fine at faster speeds, but it’s really bothering me. Tried Seafoam in the gas tank but that didn’t seem to make any difference. Should I replace spark plugs next? Trying to self diagnose as I don’t want to take it anywhere since it isn’t throwing a code at all. Thanks!