2001 ford escort 4 dorr. 2.0 sohc engine

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 vehicles where theMaf Sensors leak the silicone potting material used to protect the circuitry.
• There could be a downstream vacuum leak of the MAF sensor. or a leaking intake manifold gasket or loose vacuum hose on the engine.

• In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
• Inspect all vacuum and PCV hoses, replace if necessary
• Check for a dirty fuel filter and proper fuel pressure

Ford escort zx2's have a design flaw which causes the tube linking the crankcase to the intake manifold to burn through after a few years. this introduces a vacuum leak. you can easily check to see if this is your problem by spraying a good amount of starting fluid down around the engine, in the back and around to the front left, where the hose runs from and to. if it is bad, it will **** some of the vapors in and rev the engine for you.