have a 1996 contour
engine light keeps coming on, got a reader and code 0171 is popping up

System too lean (Bank 1)

about 70000 miles on it.....if anyone can give me a few clues where to start it would sure be
appreciated !!!

also hear like a loud rattle usually when first started.....looks like a cover for the timing chain??? rattle appears to come from there
doubt the 2 things are related?????

I think the noise....rattling type noise is caused by low R-134 ?!?
gets better when I add to the a.c.
but still getting the warning about 1 bank being to lean
adding inj. cleaner with most fillups but code keeps coming back
anyone know why???

timing chain rattle was a v6 contour problem on the 95 model...something about when the oil was allowed to settle after the car had been sitting awhile...would occur mostly on cold start and go away in a second or two...the fix was supposed to have taken place for the 96 model yr i believe

as far as the code goes, could be the o2 sensor or fuel injector???

po171-lean condition bank 1.

90 percent of the time is caused by a vacuum leak. Look for collapsed or broken vacuum hoses or a leaking intake manifol gasket.
In most cases a malfuntioning o2 sensor will trip a code specific for the sensor itself.

thanks very much
I can sure look for some vacuum hose problems !!!!!

may the wind be at your back !