" Seafoam? Using that crap on your car is bad news. NEVER use Seafoam on ANY BMW. Ever. I wouldn't use the stuff on my lawnmower.
if you're worried about running rich and fouling your plugs then stay far away from Seafoam. One little drop of that crap will foul plugs, o2, basically any fuel/ignition system component. It's like dropping TNT into your gas tank and going for a drive.
Sigh. Please never again! "