In Reply to: F150 4.6 saga continues posted by lonestarjeff on January 17, 2019 at 17:52:49:
I pulled both upstream O2 sensors, both came out surprisingly easy. The right side is the black one.
Start-up this morning was very smoky & the engine runs worse than yesterday. Oil pressure shows good, but haven't put a real gauge on it. There was no oil burning going on before I did the timing chain job, so I'm inclined to think something I did started or worsened a leak-down around a valve on the right side. One cylinder must be fowled enough now to cause misfire. I'm trying to decide where to draw the line throwing parts at this point. If I'm right about the cylinder fowling it's just going to drive a new O2 sensor on that side crazy(not to mention that plug).
I had this same smoking issue about 75k miles ago, but it self-corrected when I switched off of synthetic oil, so I'm debating with myself whether to sink more time & money into it or get rid of it.