The check engine light on my 2005 Vue came on. The scanner came up with one code, P0172, which points to a dirty or faulty mass air flow sensor. It also states it could be a vacuum leak or fuel pressure problem. Could a poor gas cap seal cause this code? It has come on twice in the last 3 weeks, both times after I filled the fuel tank. I fiddled with the cap and the light went off the first time but shortly after I refilled the tank, the light came on again. I got the same code again with the OBD11 scanner. Should I begin with replacing the gas cap? It is a 2.2 engine with manual 5 speed transmission.