Anything in the intake track will disperse the oil over all the cyls... when you let off the pedal the vac goes up and pulls the oil back into the intake and will dump it in all the cyls and can make it look like there is very little signs of oil.. I had a hole in a intake runner and it pulled a qt of oil in 35 miles and dumped it out both pipes... the muffs had a lot of oil in them