We just drove from Kansas City to Breckenridge, Colorado, so we're high up in the Rockies. Jeep did fine. One thing though, my air vents don't seem to work properly, especially going up hill when the engine load is high. I assume vacuum is low and we're at a high altitude. As soon as engine load comes down the vents open again. So I assume a vaccuum leak somewhere in combination with these high altitudes/high engine loading going up the Rockies.

any thoughts? anybody experienced anything similar?

Thanks, Jeroen

 

sound like the check valve in vacuum canister is shot not holding vacuum to keep vent open to dash

 

adding a check valve in the vacuum line from motor to cannister should cure this