[TR] TR6 - Help Wanted

[dctr6 at optonline.net]

  I've just returned from a 2,630 mile Southern trip to The Mitty at Road Atlanta, some touring around Charlotte and a trip to the NC shore, all in my TR6.  All went extremely well until about 100 miles from home.  The car starts and idles fine, and runs in the low revs OK but will not run over 4000 RPM. It just seems to choke - it made the long hills on I-81 in Pennsylvania a real chore - I'd get going 75-80 mph at the bottom of the hill and would barely be doing 55-60 at the top - it just wouldn't go any faster. I checked for the obvious (vacuum hoses disconnected, etc) but found nothing. My only theory so far is a possible carb problem (possibly a torn diaphragm in one carb?) but I can't get the car into the shop to check it out  until next week.  Any other ideas where to look?  Thanks.
Dennis Culligan, Highland, NY / 1976 TR6 CF57948U - TR6IUMPH