torqueisfun

I am getting a CEL for Bank 1 Lean. This happened to me about 9k miles ago and it was the PCV valve. I believe it is the same issue again. The oil dipstick is under vacuum, I can hear it when I pull the dipstick out and the cars idle increases. It also appears that the oil filler cap is under vacuum, The idle speed jumps up when I remove the filler cap. For the mechanics out there, does it sound like PCV again to you. I am kind of surprised it would need replacement again so soon. Other than a tune and ROW air boxes, it is stock.

glennhl

Under normal conditions the PCV system will pull a slight vacuum on the engine crankcase. However, if the PCV valve sticks open or the spring breaks, it can pull too much crankcase air into the engine inlet causing it to lean out. Before you fix it, just look really hard for other sources of a vacuum leak.

torqueisfun

Thanks for the advice. I tried spraying brake cleaner around known leak areas that others have mentioned but didn't notice any change in the idle speed. The thing that has me most curious is the abrupt idle change when I remove the oil filler cap. You can feel the vacuum pulling on the cap and once it is lifted up a bit, the idle speed increases by a few hundred rpm immediately.

glennhl

That is a good way to look for vacuum leaks. I went out to my car, which is running fine and I took off the oil filler cap (710 cap ). I can hear a vacuum sound and the idle speed raises by around 100 to 200 rpm (tough to tell using the stock tach).

Mort

There should be a way for metered air (downstream of the MAF) to enter the crankcase to balance the air drawn from the crankcase through the PCV. Maybe that line is plugged or pinched causing vacuum to build in the crankcase. Not sure where it is located on our cars.