Contour Enthusiasts Group Archives Forums General Troubleshooting "too lean" CEL came back

My best guess as to why I'm still getting a "too lean" CEL and surging idle is a vacuum leak. (The idle is worst when cold.) But the weird thing is that cleaning the MAF seemed to fix the problem for a short time, after which it came back. Maybe there was both a dirty MAF and a vacuum leak, and the leak is worse now than it was then...

Sure its not the o2 sensor, i got the same error, i found out its my upstream bank 1 sensor, but i still have to change it, probably tommorow.

dudes, before you go and change your o2 sensors, do what i did. i too got code 171, which means bad o2 sensor. i unplugged my connectors on the one by the manifold. cleaned it and blew it out. reset the computer, and the cel light hasn't come on since. its been about 1000 miles too. my last tank i got 27 mpg. so a bad connection or dirty one could be causing your light. i paid the $80 for a diagnostic check at my dealer for nothing. but it probably is getting old, after all its stock with 103K on it. i will also clean my maf to see if it helps anymore. try this, it may save you some dough.

i did that too, sort of, i took it out blew it through it even with a pump to really blow it out, put it back in, did not reset the computer though, still have the light.prob should have reset it , but wouldnt it turn off if it worked properly.

Try that before sending $$$ on a sensor.

That's a good point, I recently messed with the O2 sensor connectors to check their voltages. Maybe they got gunked.