My 2003 Nissan Pathfinder has 50,000 miles. The engine light came on and I had to take it to the dealership to have them turn it off. It apparently was the air intake sensor. Ever since I have been burning through oil, however, there is no noticable leak. Today my trucks RPMs would not go above 3 and it was downshifting as I was pressing on the gas petal. Can someone guide me in the right direction? I have some knowledge of cars, but do not want to get screwed by the dealership. Thanks so much!

When the engine does that it means either the mass airflow sensor, the O2 sensors or the throttle position sensor has died. You can have most any auto parts shop scan the codes and reset the light for you for free...