Hello, got a question about my '99 500 EFI P.S. After driving at various speeds for any length of time, my 500 wants to idle at 3000 -3300 RPM. After almost a minute it idles down to 1800 - 1900 RPM. It didn't do this before and showed up some last year, worse this year. Air box is clean, new plugs, clutches cleaned, belt deflection good, clutches are aligned, checked over thouroughly. This sled gets a lot of miles, so bad fuel or gunked up from sitting should't be a factor. :face-icon-small-con What would cause this? Any ideas?