I just had my 98 fatboy up in las vegas for bike week & had a problem riding up into the mountains. Lost top end throttle around 8500' - 9000' elevation. Running 60mph, tried to go about 3/4 throttle & had nothing & the bike then died. Pulled over & had to choke it to start it back up, then it ran ok thru 4th gear but as soon as i tried to go to 5th gear same thing. Got back to hotel & changed plugs & cleaned air filter & bike ran ok riding in town but really didn't have any top end power? Checked with a couple local shops that said it was strictly altitude but i have had bike up 9500' feet outside tucson before with no problems, so I'm just not sure. Running low rpm's in 2nd or 3rd gear I think i hear a whistle (that no one else seems to hear) & wonder if i may have an intake leak or something that might cause what happened?