Altitude fouls cylinders?

[GTRS Fiero]

Years ago, I droge a '77 Dodge through Colorado.  It was a 440 V8.  The timing was not changed, and 2 cylinders got fouled out.  Admittedly, that van had about 700,000 miles on it.  I was told that the problem was that the timing was off for that altitude.

Does the Fiero have to be re-timed for different altitudes, or do the MAP and O2 sensor inputs allow the ECU to handle everything?

[Fierofool]

Once I was talking on the phone with olejoedad of the Capital City Fiero Club and I don't remember exactly what the subject matter was, but he said that when they do the mountain stuff they stop and disconnect the ECM power at the C500.  Then they reconnect it and the ECM adjusts for that altitude, using the correct air/fuel mixture. 

[GTRS Fiero]

Hmmm. So, it can adjust, but not on the fly.