Nissan Repair: Nissan xterra 2000 engine problem, mass airflow sensor, nissan xterra

Question
2000 Nissan xterra. Live in LA & driving in high altitude in park city, ut. Yesterday driving down mt. 6000ft pass seemed like gas wasn't getting to engine & car slowed from 60 to 40mph. Check engine light came on, pulled over then w/in 5 mins light went off & car resumed to normal. Drove another 4 hrs over the next day. Today drove fine until three hrs into trip I was parking & it felt like it was going to stall, put in nuetral then parked. Supposed to drive back to LA tomorrow 12 hrs w baby- have a mechanic in LA but wondering if I should take it to - gasp - dealership in AM? Don't *think* I've had air or fuel filters changed in at least 3 yrs if ever. Help!

Answer
Heather,

The Xterra compensates for altitude with a mass airflow sensor and a manifold absolute pressure sensor.  So, a basic filter change might get you back to LA.  Otherwise, a new set of plugs is in order.  There is no fuel filter so it is just a matter of changing the air filter and see how it goes.