Pull the manifolds and clean them properly.
Don't be LAZY!
Even if you do the dousing with B12 Chemtool you will want to change the oil afterwards.
Enough cleaner can get past the rings to dilute the oil enough that I wouldn't even think about driving on it afterwards.
Also cleaning that way is surface oil cleaning at best. It WILL NOT remove any build up and that's where the main problem issues arise from.
