Pontiac Vibe Loss of Power

My daughter drives a 2003 Pontiac Vibe with automatic trans. She just recently moved from Michigan to Colorado. Once she hit the mountains West of Denver, she couldn’t do over 45 mph. We had it checked out and replaced a clogged catalytic converter a couple of weeks ago. Today she called and said that she still can’t get over 45 at higher elevations. The car seems to run better when she enters a tunnel or gets down to lower elevations.

Any suggestions?

Get a manifold vacuum check,I conclude no “check engine” light.After that checks good, head to fuel pressure check.All maintiance up to date?

It was serviced just before she went out west from Michigan. I’ll have to check with her on the check engine light. It did come on before we had the converter replaced.

Just checked with her, NO “check engine” light.

It’s normal for an (non-turbo) engine to put out less power at high altitudes because the air is thinner. The Vibe/Matrix (I have an '06 5-speed Matrix) doesn’t have a lot of power to begin with. Lax maintenance like a dirty air filter will exacerbate the problem.