Trouble code P0171

[4x4mike]

It seems every offroad trip triggers a P0171 code (System too lean, Bank 1). The first time it happened was at about 85k miles and required a MAF cleaning and IAC tear apart and cleaning along with a code reset. Road driving after that was fine and no codes were triggered.

Next dirt trip another P0171. It took another 2 or 3 of these before I needed another IAC cleaning. The trigger in between resulted in MAF cleanings and code resets.

Fast forward to 138k miles and some more trips. Dust and dirt causes the light to come on. Sometimes on the trail other times on the road coming home from the trail. Regular road driving produces no problems.

My question is what I should do? I'm thinking about replacing the MAF but wanted to bounce it off a couple of you first.

I have a stock engine set up and run an oiled Tru Flow filter. I've had the light come on with and without the deck plate on. I've had two trips in two weeks. After the first week I pulled the Tru Flow and put in a Toyota filter along with the deck plate, still got a light. All the clamps and intake tubes appear fine with no holes or tears.

https://lh5.googleusercontent.com/-zLEeTjP11D8/T_XCcamOwDI/AAAAAAAAvlg/CIpxQD-uAbU/s800/IMAG1526.jpg


These are the stats for when the light was triggered.

https://lh5.googleusercontent.com/-cI6HGgKYCaI/T_XCjC3TtgI/AAAAAAAAvlo/uDRaJK_18Sw/s800/IMAG1527.jpg

https://lh6.googleusercontent.com/-OAYPdsdRn80/T_XCsOGQApI/AAAAAAAAvlw/I2UERyVYbnI/s800/IMAG1528.jpg

[paddlenbike]

I noticed last night that the rubber o-ring that seals the sensor to the intake tube is very stretched-out on mine. When I attempted to reinstall the sensor it wouldn't bottom-out and seal like it should. I had to use lube, a screwdriver and some patience to get it to work...you may want to check yours as this may be why dust keeps accumulating around your sensor. I plan to replace the o-ring soon.

[4x4mike]

My o-ring is good and tight. In fact it takes a screwdriver to pop the sensor out and when you put it back in it pops into place.

You should get the metric and standard versions of this kit: http://www.harborfreight.com/382-piece-o-ring-assortment-67554.html

I've used about half of my 2 kits on all kinds of things. Comes in handy for all kinds of house happenings. In fact the eave lights that lead up to the front door are held up with o-rings.

After some internet searching on MAF's and when people actually have to replace them I found I wasn't cleaning the sensor completely. I usually just shoot the match stick looking piece because it was always dirty. What I wasn't cleaning was the 2 wires inside the tube. They are nice and furry. I cleaned them good and put it back in. So far so good.

[paddlenbike]

You should get the metric and standard versions of this kit: http://www.harborfreight.com/382-piece-o-ring-assortment-67554.html



k. All I needed was a good excuse to go to HF.