I pulled my Throttle body and was going to make sure that the ports on the inside for my EGR and DPFE sensors were clean since I keep getting my 402 trouble code but I am wondering how dirty things are supposed to be in there. I know that you are't supposed to actually clean the throttle body since it has it's special film on it but once I pulled it off to get to the ports almost everything inside is completely black and filthy. Any suggestions would be great. Thanks.

 

I wouldnt worry about the "special coating" on the TB, even if some of the film came off, its still better than it being covered in carbon. From my understanding PO402 means excessive egr flow, which would mean that the ports arent clogged. Most people say that its probably the DPFE sensor. But it cant hurt to clean the ports while you have it off. Depending on mileage, it should be fairly dirty, but it shouldnt be really bad.

 

If you go to your local auto parts store they have throttle body cleaners that are supposed to be "safe for coated surfaces."

 

I have a 98' F-150 XL Supercab with the 4.6 L and it has 178,000 miles on it. When I pulled the EGR Valve it was very dirty. Not completly clogged but it was pretty bas so I replaced it since I wasn't able to get all of the carbon out of it. I just finished cleaning the throttle body and the intake that is behind it so hopfully that will help since I was able to clean the ports while I was at it. If it needs further cleaning I guess I will have to take the top end intake completly off and give it a good cleaning.

 

The easiest and most effective intake cleaning I know of is the BG Products induction system cleaning. It does an excellent job.