castorino220

2001 Mustang GT, i recently got the car, i have another tread below this listing whats done on the car. i put about 260 MI on the car and the service engine light came on. got it checked its P0172, rich bank 1. they said it was the O2 sensor. i changed that and within 2 days the light came back. got it checked same code came up. they said it could be the fuel pressure regulator, or the fuel purge valve. a mechanic told me it could be a exhaust leak, dirty or bad mass air, vacuum leak, leaking injector. this happened out of no where, car still runs great. please give me some ideas. where is the regulator, and the purge valve located on this car?

thank you

castorino220

i took off the MAF, when i looked from the back side on the bottom there was a little pile of sand. i am going to get some MAF cleaner and see if this fixes it. what else could it be? i find it hard to believe it is an exhaust leak, but i was told to check for 1. i was also told it could be a bad injector, to use a screwdriver and listen to each 1, and if 1 sounded weaker than the rest that would be the issue. im told that is throwing the code that its rich because it is actually lean and the computer throw more gas at it to compensate for the lean condition. any thoughts?

dawson1112

Symptoms

You will more than likely not notice any drivability problems, although there may be symptoms such as a misfire.

Causes

A code P0172 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 can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
•There could be a vacuum leak.
•There could be a fuel pressure or delivery problem

Possible Solutions

Possible solutions include:
•Inspect all vacuum and PCV hoses, replace if necessary
•Cleanthe MAF sensor. 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 fuel lines for cracks, leaks, or pinches
•Check the fuel pressure at the fuel rail
•Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
•Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

This is what the dtc manual will tell you to do .