Fastfrank

Anybody already experience a check engine light with a 0172 code every time you fill up your gas tank.

KdF

Blantantly stolen from OBDII Codes.com

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 SolutionsPossible 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

Also it could be a bad gas cap

SchooBaka

P0172 is a system rich code.
Do you top off at the fuelpump? I've seen people fill their charcoal cannisters with gas by topping off too much.

Fastfrank

Yes I do have this bad habit ! So you say that my charcoal canister may be
finished if I have done this frequently.My check engine light came off and my fuel tank is lower than 1/2. I will try to fill to the first click and see if it comes on again. thankyou

Fastfrank

Thank you .
Yes I have personnally already had a check engine light come when a gas attendant put the wrong gas cap on a nissan altima.
thanks again and God Bless.