O2 sensors work like a thermocoupler as they age they operate slower If you watch them with auto tap or some other svan tool they will be slow to switch from rich to lean. these are one of the major controls when the veh. is in closed loop, so any excessive time consumed in switching will cause the computer to over fuel the engine. They are still working but not up to speed, they are a maintenance Item that should be changed around 50,000 mile, change them with a qualit unit Bosch premium or Motorcraft. the differance is unbeliavable. Also remember any time you clean anything on the intake side of the engine, all those chemicals and deposits are being burnt, and they contaminate the spark plugs, O2 sensors and even the cats. So if you any cleaning do it before a tune ip or O2 sensor change, don't contaminate you're new parts.

 

Can someone send me a picture of a F150 engine, pref 4.6? No joke.. Because there's a weird part in my engine and I wanna compare it to a normal one. THANK YOU SO MUCH IN ADVANCE!

 

Here man, dig through my gallery.

https://www.f150online.com/galleries...ew.cfm?num=213