Jetta TDI 2006 hiccup at high altitudes?

We live at sea level, and while taking a vacation to 5000+ feet, our Jetta TDI has started to have an engine problem that seems to be a gasping/chugging/hiccuping type of problem similar to the type of problem that would occur when you are about to run out of gas. This same thing happened the exact same way last year on the same vacation, and the problem fixed itself as soon as we returned to a lower altitude.



Other possible factors: high humidity at home/low humidity vacationing. last year we replaced the fuel filter/air filter while on vacation, and the problem persisted until we returned home.



Thanks for your help!

When was the last time you had the intake system decarbonized?
TDI’s build up carbon in the intake manifold something fierce, and needs to be cleaned out physically.

BC.