The back side of the throttle blades on my 2003 Lightning look as if they've been sprayed with a dark grey/green paint. I looked at a 2001 and it has the same stuff on the blades. It looks like someone first sprayed paint on the back of the blades, shaft and screws and then went around the outside edge of the blades and the throttle bore with a brush making it thicker where the blades sit against the bore. It is not carbon - it is green and even has small bubbles in it. My 2003 has 756 miles on it and the 2001 I looked at has 22,000 miles and has the same"coating". If you remove the rubber duct from the front of the throttle body and run your finger around the opening you can feel a small, but definite step where this is. I can't imagine that it hurts the airflow much, but I'd like to know why it is there before I polish it off. It may be to help the blades seal against the bore so the idle air valve or bypass can have better control of the idle.

Has anyone else seen it?

 

I have no idea what that stuff is, when I removed the stock throttle body from my 02 Lightning it didn`t have any coating on either side of the throttle body, and the accufab single blade throttle body had no coating either. but, back in 2001 when I had a regular 4.6 f150 I added a larger BBK throttle body to it and it had the coating you are talking about, I removed all of it and re-adjusted the throttle blade to seal better and it worked just fine.

 

I think sometimes they coat them to keep carbon off?

 

The green coating is a teflon material that they use on throtle shafts and sometimes the blades. If you look at an older carb you will find it to. If thats not it might be dye from your oil or something else collecting there. Artie

 

Often a throttle body has a coating on the edge of the blades to help in preventing stickiness and seal at idle (closed throttle). If that's what it is you shouldn't really remove it.

Jody

 

Thanks for the input. I took the throttle body down to my local SVT dealer and asked them. All guesses and no answers. I think the idea of a coating to eliminate sticking is the real answer. I know my 99 5.4 F150 always had a sticky throttle on startup. The 2003 lightning does not...