Then got a check engine light P0171. Checked Google before going to my dealer, and learned that many Gen. 9 Corollas had a black intake manifold gasket that dried out and let in outside air leaning out the mixture. A new orange gasket was put out with a TSB.
Dealer changed gasket and performance really improved along with about 3 more mpg.
The code readout for P0171 from Auto Zone didn't mention the gasket. Suggested MAF sensor or big vacuum leak.
Hope this is useful to others who may get this MIL code.
Edited by BobLevine, 19 February 2012 - 06:55 PM.