mustangman03

P0172 (System too Rich Bank 1) could be your O2 sensor.

ZW99GT

Exactly. Go to AutoZone and get an 02 Sensor($40-50). Replace it(it takes all of 10 mins) and then go back and tell them to clear all the CEL's.

If that doesn't work, go get a set of NGK TR-55 plugs(~$15) and gap them at .045. If your plugs are fairly new, then just replace #2, but make sure the gap isnt too large.

highroller02

yea first thing id check was 02 sensor

MooseStang88

I found this in a old book i had, not sure if it will help you or not.

[*]The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled[*]There could be a vacuum leak.[*]There could be a fuel pressure or delivery problem [/ol]
Possible solutions include:

[*]Inspect all vacuum and PCV hoses, replace if necessary[*]Clean the MAF sensor. Consult a 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) [/ol]