John,

You're absolutely right. I didn't think that a '95 had the ability to
compensate. Thinking about it, '95 aint that old. It's still manual in
airplanes (piston)...I wonder why?
Thanks for the info.

--Mike

"John Wentworth" wrote in message
. ..

Fuel injection does not "adjust itself." You need to give it more
throttle
because there is much less oxygen by volume at ~6200ft. Opening the
throttle not only adds more fuel (via the injectors), but more air...then
it starts. The adjustment needs to be made because at idle, the mixture
is too rich (too much fuel, not enough O2), and the motor stalls (or
won't start). The power loss is due to an overly rich mixture. Airplanes
have a mixture control that is adjusted as they ascend or descend for
exactly the same reason.

--Mike

A modern FI system does "adjust itself" to provide altitude compensation
by use of the MAP sensor input to the computer (MEFI module). Lower
barometric pressure at high altitudes will cause a drop in manifold
pressure, which will be detected by the MAP sensor and cause the computer
to adjust the injector pulse width. Some new FI systems add a fuel
pressure sensor to provide more accurate altitude compensation. Mercury
now uses their own proprietary FI system, but in 1995 it would be a GM
system.

Snowmobilers riding in the mountains have had the altitude compensation
problem for years, until FI came along and solved the problem.