PO156 is the downstream(past the cat. towards the rear) Bank 2 which is left side (drivers side). Mine recently showed code PO141 so I purchased a sensor through Ford($75) And it took care of the problem(mine was downstream, bank 1). I asked Ford if they could check the sensor which was in hand and they told me that it had to be in the truck and would cost about $80 to check it. I don't know if this was to pull the code or if they would actually check the sensor itself? If your thinking of buying a sensor you might want to check out
www.carparts.com, they have sensors by Bosch for Ford trucks for about $40. Don't know if this helps you or not but good luck.
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97 F-150 Black, 4x4 XLT ext.cab,sb,offroad pack.
4" Susp. lift, 3" body
4.56 gears w/LS,Borla exhaust
35" BFG.,16.5x9.75 Weld Scorpio V wheels, Edelbrock IAS Shocks,Lift Lips,
K&N Filter, TransGo Shift kit,
Bug shield,Tinted windows
Sony ES head unit,Sony ES changer,MTX Thunderform sub,Boston Acoustic Proseries up front, Polk in rear,PPI & Coustic Amps,Alpine Alarm
[This message has been edited by Squanto804 (edited 08-31-1999).]