For about 2 months my 07 accord 4cyl has been throwing the P0171 "fuel system too lean" CEL code intermittently, with the problems that most on here have probably heard about with the stalling at red lights, in reverse, rpm issues, etc. At a stoplight, the car would also "jerk" about every 30 seconds. Anyway I was cleaning the MAF sensor and proceeded to check the air filter when I noticed that the PCV fresh air intake duct (the larger piece that clamps on) was completely disconnected from the main duct. Since this connection is nearly impossible to break under normal operating conditions, the only thing I can think caused this was when my wife had the air filter changed during its last oil change and the technician forgot to hook it back up (it's kind of hidden/blocked from view as it is).

I hooked this connection back up, and the "jerking" at the red lights immediately stopped the next time I drove it. Could this being disconnected have resulted in the P0171 code "fuel system too lean" condition?

Thanks,
Ryan