How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Dan Your Own Question
Dan, Technician
Category: Pontiac
Satisfied Customers: 24426
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
Type Your Pontiac Question Here...
Dan is online now
A new question is answered every 9 seconds

Pontiac Montana 2005 montana van engine light on and getting

Resolved Question:

2005 montana van engine light on and getting bad gas mileage obd2 say P0172 system too rich (bank 1 ) anyone have any ideas????
Submitted: 6 years ago.
Category: Pontiac
Expert:  Dan replied 6 years ago.

Welcome to JustAnswer, my name is XXXXX XXXXX I'm here to help get your problem resolved. Ask follow up questions, thanks.


This is usually caused by a failing mass airflow sensor.....You can try to clean it first with approved cleaner from parts store if that doesnt help pull the vacuum line off the fuel pressure regulator, if fuel comes out replace...If not I'd replace mass airflow sensor.


P0172 Fuel Trim System Rich (Bank 1) - With Automatic Transmission

Possible CausesSetting Conditions
  • Base engine "mechanical" fault affecting one or more cylinders
  • Excess fuel vapors in crankcase (the oil needs to be changed)
  • EVAP system component has failed or canister fuel saturated
  • Fuel control sensor is out of calibration (i.e., ECT, IAT or MAF)
  • Fuel delivery system supplying too much fuel during cruise or idle periods (e.g., faulty fuel pump, or faulty pressure regulator)
  • Fuel injector(s) is leaking or stuck partially open (one or more)
  • HO2S has failed (it may be contaminated with fuel, silicone or water)
DTC P0030, P0036, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0121, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0401, P0403, P0404, P0406, P0420, P0442, P0446, P0449, P0452, P0455, P0462, P0463, P0496, P0506, P0507 and P1404 not set; engine speed from 550-5,500 rpm, ECT signal from 50-255ºF, IAT signal from -1 to +284ºF, BARO signal over 74 kPa, MAF signal from 2.8-150 g/sec, MAP signal from 15-105 kPa, Idle Purge enabled, fuel level over 10%, VSS less than 82 mph, and the PCM detected the Short Term fuel trim was less than -17% for 40 seconds.

This code sets in 2 Trip(s).
This code will turn on the MIL (Malfunction Indicator Lamp)

Customer: replied 6 years ago.
you say if fuel come out replace ? the vacuum line or the fuel pressure regulator?
Expert:  Dan replied 6 years ago.
If fuel comes out of the fuel pressure regulator or vacuum line then replace regulator....There should only be vacuum in the line, but if there is fuel in there then it came from the regulator....usually it doesnt leak enough to see it come out of the regulator but builds up in the vacuum hose....Best time to check it is after it sits for a few hours after driving.
Dan and other Pontiac Specialists are ready to help you
Customer: replied 6 years ago.