I have a 2001 Expedition with the 5.4. On medium/heavy acceleration it exhibits a loud clatter that is very annoying. It runs strong and I've had no other problems with the engine, but I am concerned. I've read some of the posts about the imfamous piston slap and was wondering if it sounds as if that may be my problem. It doesn't matter if the engine is cold or at operating temp. Sitting in park and reving the engine does not seem to produce the noise. Any ideas before i take it the dealer? Thanks in advance, Bob

 

Usually the piston slap is on cold start ups and is most noticable at an idle. Sounds like detonation and there are many causes. Dirty combustion area(carbon on pistons and heads), vacuum leaks(lean condition) .
I would have it checked soon before any real damage is done.
Jimmy

 

Yeah, I'm gonna call in the AM and schedule with the dealer. Was hoping to know what I was talking about before I called in. Thanks for your help

 

Afternoon,
Not sure if this will help on the diesel sounds, but it seemed to work on mine. I was getting a diesel sound when I accelerated, at a light or up a hill. The noise absolutley drove me crazy. A few weeks back there was a thread, not sure of the title, where a member flush and filled his transmission and it solved the problem. A mechanic at the dealership told him it would only work on the 4070w(?) transmissions, not the other. I wouldn't think that it would actually work. I have a 99 F150 4x4 S/C with just a hair over 80,000 miles on it. My neighbor works at a Mazda dealership and has access to the shop on weekends. He was able to flush and fill the transmission for me this past weekend. I may be crazy but it seems that the noise is gone or is not as audible.
I have the 4070w transmission. I think that is the model, I'm to lazy to actually look it up. I know it isn't the R4100, if that is the other one.
Hope you your able to take care of the problem.