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?