Does this look like the right part to replace the 2 upstream O2 sensors on my 97 150 XLT w/ 4.6L? My mileage is getting really lousy, and with 84K miles I am debating replacing these things, even though there is no check engine light...

http://www.rockauto.com/ref/Motorcra...tml?dy-832.gif

 

It is the right part, you can verify under it "catalog" at www.motorcraft.com
At 84k, you should replace them. The upstream ones are almost a maintenence item and should be replaced every 40-50k. I don't know what rockauto wants for them but you can get "Bosch" ones at Pepboys for around $50 each (Bosch is oem to Ford).

 

Thanks, I see that the local Advance Auto parts has them for $43. How hard are they to get at? Easier to take off the wheels and go in through the fender wells, or from above? Or go underneath? I do have the special socket someplace, although the last time I replaced one of these was on my Nissan, and after buying the socket, I found that an open end wrench was all I could get on the thing anyway...

 

There are a few posts on installation, here's one for a 5.4 but I think yours should be very similar:

https://www.f150online.com/forums/sh...hreadid=190863

If I could do it, you can, too I just had to crawl under my truck, pretty straightforward to do.

 

easiest and fastest way is to remove the wheels and plastic inner fenders. less than 45 minutes for both sides, 22 mm box end wrench (includes putting away tools)