I have a 1999 f150 5.4 4wd and the engine would not idle so I removed the throttle body and as suspected it was all lined with sludge, mostly on the other side of the butterfly. After cleaning it with a recomended solvent and reassly, all works quite well again. I noticed that on the 90 degree, that body bolts to is full of that oily guck. I cleaned inside as best as I could without removing it. Is it normal to have that sludge at 140 thousand miles? Should I continue deassembly at another time and continue cleaning or just not worry about it?

 

I clean mine every 30k miles or so. Very normal. I would also clean the elbow that you are talking about and make sure the idle air sensor ports are clean.