I have the triton 5.4 and I am getting a very loud whining noise when I start it. I have taken off the serpentine belt and replaced it checked all pulleys to see of they rocked which they didn't I am stumped..... only thing I can think of is that it may be an intake leak but the sound goes away after vehicle is warm. Any advice would be appreciated

 

Might be a vacuum leak. Use some carb and choke cleaner and sprary around all the hoses and fittings while the truck is running. If the engine speeds up when a spray and area, that hose or fitting needs to be replaced or tighten.

 

Keep driving and see if this problem increases or not. If not then try and take it to the dealer.(If you cant figure out the problem at all)