My quick thought is that the mechanical fuel pump is starting to go ... they lose pressure at high rpms and don't seem to affect idle at all ... I had one that was going bad and the kids could kneeboard (20 mph) .... but I could not slalom because the engine would starve for fuel ....
Mechanical fuel pump easy to get (skidim.com) and my best guess ....
Keep a tight line, and a smile on your face. Peace out.
2008 Prostar 214 MCX
Previous 93 Prostar 190 1.5:1 GT40
"Left Foot Forward and preferring girls."