After just cleaning my throttle body (again), I was wondering how that thing gets that black film in it. Looking at everything that is upstream (air filter side) of it, the only things I could figure are these. First is a K&N or other oiled filter media. This oil plus the dirt they don't filter can stick to the inside of the throttle body. But I am not using my K&N right now while I am doing my own little air filtration test. The second is the crankcase breather hose. This would take the evaporated oil fumes from the crankcase (is it called burn off or whatever?), and put them in the airflow before the throttle body. My question is: Do any of you that have a filter on their crankcase breather (side of valve cover) have any problems with dirty throttle bodies? Are there any drivability problems? Or do the filters just look good? Maybe a filter there instead of the hose connecting the valve cover to the intake could solve most of our problems with dirty throttle bodies. Just an idea to toss around.

Dave

 

no drivability problems with my breather. I dont have much problems with dirty TB so I cant say anything about that.

 

some people were saying they had hesitation due to a filter there, but I don't really know if that's been a constant, or just one or two people.

I am going to be doing some wholesale cleaning of that area this weekend.