i have a 1999 f-150 super cab 4.2l. my truck runs fine when i am driving around, but when i stop and let it idle for a few minutes the truck shudders real bad and starts to idle real bad. i took it to auto zone and checked on their computer it said "bank 1 too lean, bank 2 too lean". i also took it to a ford dealership and used their computer. they said my fuel pump was bad and i needed an oxygen sensor (sensor 2). i replaced both of those items plus 2 more o2 sensors plus a complete tune up. it still does it. i have to replaced one more sensor (passenger side - after converter). someone told me it be a M.A.P.P. sensor. i am tired of buying parts to solve my problem. someone please help me!!!!!!

 

Wrong Forum, but I would be willing to bet the Wife's Magic Chef that it is the Mass Airflow Sensor. Had a 1991 Ford Probe.... (I know, I know) that did the EXACT SAME THING. Dealer replaced Fuel Pump, O2 Sensors, Injectors, Sparkplugs, New (complete) Intake, and then told me the Transmission was BAD and that was causing the problems.. Still not sure how he expected me to fall for that one, but at any rate, was monkeying around under the hood and heard a HISSSSSSSSSSSSSSSSSSS.
Saw the CRACK in the intake about 1/4 inch PAST the Mass Airflow Sensor. I wrapped it up with Duct Tape and put another 130,000 miles on it. Problem free.
The Mass Airflow Sensor is NOT going to give you a trouble code in this senario, because for all it knows, it is reading right. The air that is leaking PAST the sensor is not accounted for, and therefor makes it run very lean. The O2 sensors are trying to adjust the mixture for this, but they can't adjust for an irregular mixture like that.
I would check to see if the Mass Airflow Sensor is bad, or if there is a loose connection, or crack in your intake tube or body itself.
Thanks,
matt Koser