Sludge in TB and plenum

It is most likely oil from the K&N filter. This is a common occurence with K&N users. Doesn't hurt anything, but you might want to use a little less oil on your filter next time.

Although the K&N doesn't help, the 4.0L is prone to pull an extremely small amount of oil through the breather by the oil fill which tends to build up to a residue or sludge if not cleaned out. My 92 Ranger does the same thing w or w/o the K&N. Supposed to have the throttle body and intake cleaned occasionally. I can't remember the mileage interval off the bat though. Rich

Last time I looked at the throttle body on my Father's 4.0L Ranger, it had the "Do Not Clean" stickler on the top. No mention of cleaning the throttle body is in the maintenace guide. However, I suspect it might not be a bad idea - just be careful what you clean it with. It theory the throttle body as a special coating to prevent build-up. From what I have seen, it doesn't work, or at least not very well. However, if you want to see real crud, I'll send you pictures of the intake tract of my SO Plymouth mini van.

Regards,

Ed White

FDRanger1969 wrote:

So does mine, and I don't think its in my manual either. The dealer recommends they do the cleaning which is somewhere around a $100 if I remember correctly. You're quite correct that the special coating on the TB is easily damaged if the wrong chemical is used to clean it. Advance Auto parts carries a couple of different brands of TB and intake cleaner for fuel injected vehicles. As far as real crud goes the valves on my 87 Cougar 3.8L might take the cake. There was so much carbon buildup on them if the engine could handle the pressure and heat w/out exploding I probably would have had diamond coated valves. ;-) Found out when I did the 100k mile preventive maint. head gaskets that the 3.8L engines seem to require. Rich