I have a 2008 Uplander with 3.9L engine. I have a couple of codes coming on, they come back after a short drive after resetting them, usually P0172 and P1174 together, sometimes one or the other.
I started by cleaning MAF sensor with no change. I then tested fuel pressure at the rail, I got 60 psi with key on but engine off, and 67 psi with engine running at an idle. This seems a little high, the correct operating range I found was 59-62 psi. I was going to test the fuel pressure regulator but this engine doesn't have a vacuum controlled regulator, it has an electronic unit on the return fuel line. I don't know how these work or how to test them.
Is 67psi at an idle too high? How can I test the electronic regulator on this engine?
Thanks for the help!