On Jan 20, 2014, at 2:07 PM, KevinPGilleran <kevin@GILLERANENERGY.COM> wrote:

All,

On my last trip out to the Grand Canyon and then circling clockwise around
to Zion I found that my 1991 westy had problems with what I can only imagine
is the altitude (4970 ft at Kanab Utah). I could barely get the van up to 50
miles per hour the entire time we were at elevation. But once we dropped
back down into California and were back on highway 5 (400 feet or so) we
were back up 70 mph no problem.
Any ideas of where I should start on this issue would be much appreciated.

Your '91 says it requires 91 octane on the fuel cover door IIRC?
Is this a change in altitude performance for your van?
Do you use 91 octane?

My performance suffers at higher altitude as well, but then I have an engine
conversion (Subie) and always use 91 octane. I guess I wonder if this is the
first time this has happened in your travels at altitude, or if it's just been a long
time since you were driving your van at that altitude?

bob