What could be causing the lean conditions on bank 1 and bank 2 on my 1999 Ford Taurus SE?
(2012-02-01 15:20:14) 1. Says: it has to be lack of gas going to the injectors ! it could be the fuel regulator not letting enough gas get to the injectors.2. Says: It's a dirty mass airflow sensor 98% of the time. Remove it and you'll see a two tiny stems with a tiny wire across them that is dirty. You can purchase cleaner for these sensors. I use a soft touch with small crafts painting brush and soapy water to clean them (been cleaning them long before cleaner was invented). Two tamper proof screws #15 attach the sensor and one has a sealant plugging it so you cant remove it (Ford wants you to buy a new one every time it gets dirty). I cut the head of the screw so a flathead screwdriver will unscrew it or you could try to grab it and turn it with needle nose vise grips.Other less likely possible causes: vacuum leak, fuel delivery, bad airflow sensor, leak in hose from airflow sensor to engine. I immediately clean the sensor and then monitor the fuel trims for correction to see if it was the cause before breaking out more tools to diagnose. You'll have to clean it, clear the codes and test drive it for a bit to tell assuming you can't monitor fuel trims.3. Says: Sure as heck you have a plugged fuel filter or low fuel pressure which can be easily checked on the fuel rail under the hood. If the fuel pressure is low, change the fuel filter first. If the pressure is under factory spec. after the filter change you need a new electric fuel pump which is inside the miserable gas-tank.
Believe me, Auto Zone wouldn't have a clue. It takes a vary expensive piece of diagnostic equipment to find the proper code and the mechanic has to be sharp enough to test before repairs are made.
The non-mechanics at Auto Zone would be chasing their tail around a tree trunk.4. Says: It could be a bad oxygen sensor. Most auto parts stores like Auto Zone will read the computer codes for free and get you pointed in the right direction.5. Says: Low fuel pressure. Plugged filter or bad pump. Tag: What could be causing the lean conditions on bank 1 and bank 2 on my 1999 Ford Taurus SE?