In addition to the re-occurrance of our sudden stalling issue, our X type sprouted the above lean bank codes. Thanks to the great info on the forum I learned about two possible sources for vacuum leaks. VIZ the IMT or Intake Manifold Tuner O rings, and the PCV hose. But there is a third possibility that should not be overlooked, and that is the Power Brake Canister Vacuum Pipe. There is a plastic check valve in the pipe that deteriorates from engine heat and cracks. I started off changing the IMT rings and cleared the codes but after a few days the CEL popped up again so I started snooping further and found that the check valve was in poor condition. When I popped the pipe loose from the brake booster the check valve broke in half. At $80 they're not cheap but it fixed the problem. A note on the PCV hose. If your hose is in otherwise good shape but the ends are a little sloppy and you're worried that that may be a vacuum leak source, try clamping the ends with a couple worm drive hose clamps. A new hose is $15.00 and surprise...... comes with hose clamps. Hope this helps someone.