189 Fuel system was lean at part throttle - Left or Front HO2S - Fuel control
There are two O2's but only the top one on the exhaust manifold is fuel control. This code is for data from the O2, that does not mean it is bad.
Common reasons for this can be a bad O2, low fuel pressure, or excess unmetered air.
Logicaly, you should probably look for air leaks. these can be in the plenum between the MAF and TB, or vacuum leaks.
The most common vacuum leak tends to be in the PCV system. A short rubber hose between the PCV vacuum pipe and the PCV valve fails due to oil and heat. This is under the exhaust manifold on the PCV oil baffle and not the easiest thing to get to.
