Dodge Repair: fuel injection too rich, dodge neon, contaminated fuel

Question
I have a 2001 Dodge Neon it shows a code PO172 I've had it in the shop and they said they fixed it.But I drove a little under 100 miles and the light came back on,so I checked it with a drb2 and it's the same code. Any ideal what could be causing it? Any thoughts would be appreciated.Thank You

Answer
Basically anything from contaminated fuel to a failing PCM can cause this DTC. In order to narrow down the root cause everything related to the fuel system will need to be tested. This would include fuel pressure and volume, O2, MAP, TPS and ECT sensors and their related wiring. The mechanical engine system would also need to be tested as well as the evaporative and exhaust systems. Needless to say this is a very involved diagnostic that will require not only a good scan tool but specialized knowledge and tools to properly diagnose.