service engine soon ===engine code P0171

hey guys...can some please help me.... i was driving my 99 eclipse rs. up a hill when my service engine light came on.. two minutes later my rpm's drop to 100 rpm's and bounce right back up...... the engine feel like it was going to shut off but did not..... i good thing there was a Autozone near by, i went and use a OBD II scanner and got the code P0171 {sytem too lean} bank 1.............please help thanks guys

that code just popped up in my truck last week, try replacing the pcv valve if it has one, that fixed mine...other fixes are to get a bottle of mass airflow sensor cleaner and clean the maf sensor. alot of times a dirty maf can cause the code.....it would also be a good idea while cleaning the maf to get a bottle of throttle body cleaner and clean that as well, it could also be the intake gaskets...but try the pcv vavle first its the cheapest

A code P0171 may mean that one or more of the following has happened:

The MAF (Mass Air Flow) Sensor is dirty or faulty
Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicleswhere the MAF sensors leak the silicone potting material used to protect the circuitry.
There could be a vacuum leak downstream of the MAF sensor
Possible cracked vacuum or PCV line/connection
Faulty or stuck open PCV valve
Failed or faulty oxygen sensor (bank 1, sensor 1)
Sticking/plugged or failed fuel injector
Low fuel pressure (possible plugged/dirty fuel filter!)
Exhaust leak between engine and first oxygen sensor