Contour Enthusiasts Group Archives Forums General Troubleshooting Fault code 171 help

I have a 96 Contour with the 4 cyl. It has about 70K on it. I have replaced both O2 sensors about 2 years ago when the check engine light came on (guessing). It fixed the problem. The light came back on about 6 mos ago. I took it in and it had a dirty mass airflow sensor. The light came back on. I bought a fault code reader yesterday and used it. I get fault code 171 which is "system too lean bank 1". I have no clue what to fix. I see something that says "rear" O2 sensor, but that shouldn't have failed so quickly. Right? Does this mean that I just need lots of fuel cleaner additive? If so what works best. Every product you see says it's the best.

Help!

Steve.gould@apawood.org

well, you are not alone with this problem ... I have exact same problem (P0171) ... The stealership told me the mass air flow sensor was at fault (out of specs). I will be installing a new one (rebuilt Cardone at $100) this week-end.

From what other users here have said, I gather that the MAF on our cars get contaminated pretty easily so they need to be cleaned regularly with some electrical cleaners that leave no residue.

either too much air or not enough fuel ...

You may also want to:

- check fuel pressure (maybe your fuel filter is clogged)
- check PCV system
- check EGR system

All these can lead to lean condition if faulty but I doubt that's your problem.

I think it's a shame FORD does not issue a recall on this crap. Dealers make the money and we have to suffer.

Good luck,
iougs -

Welcome to CEG!

Even though you have low miles, a 96 is bound to be suffering from a vacuum leak in the rubber connector to the PCV valve. Checking fuel pressure would also be prudent.

Luck!

Thanks everyone. I'll check out the items suggested and repost the results.

Steve

Pay attention to what rogerm60 said.

If you replace the PCV valve, stick with a Motorcraft.

Steve