Hello all. I'll get right down to the problem. I have a 2006 5.4 f150. It has an edge CTS programmer, long tube headers, no cats, and a full 3 inch exhaust. The headers and exhaust setup has been on the truck for a couple of years now with zero problems. Recently I have been getting a code, p0132, upstream driver side O2 sensor. It comes on right as I start the truck or soon there after. A couple of times I cleared the code and it wouldn't come back for a few drive cycles, but usually it comes right back.

So yesterday I replaced the sensor, cleared the code, and have gone through about 6 or so drive cycles with no light. Now tonight it has come back on and seems to be repeating the old problem.

I am not sure what to do next. What are some other things I should look at to help diagnose this problem? I have registration coming up and need the check engine light gone before I go to smog it. Thanks all for the help.