markova

2003 F150 5.4 4WD "service engine soon" Po155 oxygen sensor code. Was told this is bank 2, sensor 1 upstream. Can someone verify this and where is this sensor located in my truck exhaust? Can I replace this myself and what is involved. Thanks.

presto666

it looks kind of like a 7/8? bolt with a wire coming off it. its on the y-pipe somewhere before the cat. its easy to replace, but try to use a deep 6-point socket to get it out. its kind of chincy, so if it breaks, youl be using vise grips. use some penetrating oil first, and use some anti-seize compound on the new one (dont get ANYTHING in the vents on the end of the sensor, or your wasting your time) otherwise, its simple. only as agrivating as an oil change. good luck