I have the code P0171 and have changed the MAS. After a week running the car the check engine light came on again. The car runs fine with no side effects. I also checked the gaskets and have found no leak. I dont know what my next step should be. I dont want to spend a lot of $$ taking it into a shop since they were the one to tell me to change the MAS.
Should I change the O2 sensor next? Dont know what to do.