Originally Posted by
hammon
The codes that came up were PO171 and PO174. Says if the two are set together suspect a fuel pressure condition or maf sensor fault. I replaced the maf sensor and the light came back on about 15 miles down the road so I figure it must be the pressure regulator. Do you think it could just be the fuel filter? I'm really not sure what to do but thought changing this regulator would be a quick job and has turned into a big problem.
Those are very common codes,and are NOT indicative of a bad pressure regulator. 99% of the time, those codes are set due to a vacuum leak allowing air into the intake,thus causing a lean condition since the air is not metered through the MAF.
Check all of the vacuum hoses-there's a rubber "tee" fitting that seems to usually be a problem piece after some age. It won't look too bad visually if you don't look it over really well, but it's the source of most all of those codes. It could also be a bad set of O2 sensors, but the vacuum leak is more than likely your problem.
JL