CzarKJ
Full Access Member
Well I really thank you for the advice. I'm going to have to have my mechanics track this down since in MA we have yearly inspections where that will fail in a instant.I had that same P0171 off and on for over a year after I swapped in my new engine. Replaced a bunch of vacuum hoses but it would still come back - seemed to pop up after the engine was at idle for a while when fully warmed up (didn't matter if it was winter or summer.) I figured that one or more of the gaskets around an intake runner on the left side of the engine had a very slight leak that was amplified when the engine was at operating temp. And an engine at idle draws more vacuum so that's when it set the code. Engine never ran any differently so it seemed the leak wasn't that big.
Good news is I haven't had the code since last summer. Not gonna go after the source of the leak unless the code comes back. Maybe you'll be in the same situation. Does yours run rough or seem like it has a miss?
Bob
Since I changed the sensor runs fine. Not smooth but it never has been.