Some reasons for running rich
From TSB,
The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The code sets when the adaptive fuel tables reach a lean calibrated limit.
Fuel System:
�· Excessive fuel pressure
�· Leaking/contaminated fuel injectors
�· Vapor recovery system concern
Base Engine:
�· Oil overfill
�· Cam timing concern
�· Low cylinder compression
�· Excessive engine wear
Powertrain Control System:
�· PCM concern
Induction System:
�· MAF contamination
I would suggest cleaning the MAF first and this is the cheapest thing to do.
MAF cleaning.
http://www.contour.org/mods/mods.php?s=howto&displayid=36
and
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=zetecmaint&Number=989728&page=&view=&sb=5&o=&fpart=1&vc=1
and from Autozone. In addition, you don't need to remove the clamp next to the upper air filter housing. Just spray through the housing. You do need to remove the clamp between the MAF and Inlet Air Duct (accordian tube?)
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1b/cb/25/0900823d801bcb25.jsp
