A couple of weeks ago immediately after washing my '07 3.0/AT I experienced an intermittent misfire and a P0171 (Bank 1 Lean) code, I pulled into my parking space at work and let the car sit all day. After clearing the code I drove home and the car has been fine since. Yesterday I gave her a good bath and the P0171 code triggered again which is leading me to believe that water is getting into somewhere that it shouldn't. On both occasions the hood was never opened. I'll note on both occasions the car had been idling in heavy traffic for extended periods of time

Any known issues of water intrusion into the X-types electronics or excessive idling causing this? The brake booster line, PCV hoses, and intake boot appear to be in good shape.

Thanks

 

Blownkitty, odds are, based on what you are seeing, you are getting water into the plug for the ECM/ECU and that is causing the code. The ECM/ECU sits under the cowl. So, if you wash the car, all the water runs down the windshield, into that cavity. That is where I would start. The next thing that I would try is getting the car running and then start spraying limit parts of the car. Start with say spraying the front of the car. Does the CEL come on, spray the wheel wells, etc. Start low on the car and work your way up. Atleast then you can narrow down where the water is running to cause the issue. Shouldn't take all that long to figure out.

 

Thanks Chris, I cleared the code this am and took her out for a 500-mile spin from 'Vegas to Rachel (AKA Area 51) and back, not a hiccup the entire trip.

After thinking about it more, I'm beginning think that it has more to do with idling for long periods of time, the cavity where the ECU connector plugs in was dry with no signs of water seepage, and a car idling draws significant vacuum. I'll have a go at it tomorrow with a can of starting fluid, and it probably wouldn't hurt to clean the MAF with CRC MAF Cleaner while I'm at it. Today was longest trip that I've had it out on, passing was a breeze with acceleration from a steady 65 to 100+ with confidence an no real effort on the part of the car.

Chad