Q: Saturn vue 2005 check engine light most of the time P0172 errors.

P0172 means the fuel system is too rich; rich beyond the ability of the closed loop system to compensate. It might be a vacuum leak, a mass air flow sensor, or a fuel pressure regulator problem. At that age it could even be leaking fuel injectors. But don’t run out and buy all those parts yet. Fixing a car by replacing parts until the problem is solved can get very expensive very quickly. You need to have a proper diagnostic process. You can get the car checked out at your convenience by contacting YourMechanic. They can send a technician to your home or office to check out your Saturn and let you know what is the solution.