P0171

[tfish64]

2008 BMW 328i Sedan

Replaced valve cover gaskets and eccentric shaft sensor over the weekend. Broke the crankcase vent hose and replaced that too. To do that, I unbolted the intake manifold and raised it just enough to get my hand underneath to attach the two end clamps of the crankcase vent hose to their respective mates. Rebolted the manifold to the intake frame. Disappointed that rough idle did not subside, but needed to replace the valve cover gasket anyway due to leaking oil so thought ESS replacement was worth a shot. Now I have rough idle and a RPM bounce whenever at idle now. Cleaned the MAF and inspected intake boot for tear and visually inspected all other vacuum lines I could see. Still throwing the P0171 code. Your board suggest replacing intake manifold gaskets. Should I do that ahead of MAF replacement? Any other thoughts?

[Luccia at Pelican Parts]

First thing to do is perform a smoke test to make sure there are no vacuum leaks. If you do not have a smoke tester (they're expensive) Pelican Parts - Smoke Tester, you can have a shop do it for you.