My friends 97 just recently started having EGT problems. He's barely getting any boost, and his EGTs skyrocket at WOT and are about 100*-150* then what they usually are. Another thing, is his turbo (stock) isn't as loud as it was before. You can barely hear it now. We already checked for boost leaks, so I'm assuming its got something to do with the turbo. His truck has a 5 plate with a AFE stage 2 CAI and a 4" straight pipe.

 

Remove it and check for abnormal wear. See how much the shaft moves up and down, and see if the shaft moves back and forth. Chances are, he's needing a new one.