My wife has an 06 EB Expedition and she was turning into a parking spot at a restaurant this evening and I was standing on the sidewalk since I had met her there to eat. When she turned left into the spot, her truck made a knocking sound like it was out of oil and almost died. She backed up to get straight and it stopped. I let her take my vehicle home and I took hers, it seems to be surging at 75 mph or so and doesn't have much "oomph" at take off. Put gas in it for her and as I pulled away from the pump, it died. It started and I drove it home(about 30 miles) and it was sluggish and surged but never missed or tried to cut off. Turned left into my driveway and the "knock" started. It stopped the knock and idled fine so I turned it off and waited a couple of minutes and it fired right back up. It has 174k and I changed plugs and all COPs about this time last year. The last time I had the codes read, it said something to the effect that both banks did not meet emissions efficiency. I know that is contributing heavily to the sluggishness, but would it cause the knocking sounds?

 

If only when moving then it's a bad wheel hub.

 

Very, very low of oil. She had been doing a good job of keeping up with the service on it and let things slide. Had to add 4+ quarts, it was tense around the house for a while to say the least.

 

The big question is how it could be down 4 quarts, because it shouldn't go through that much oil between changes? How long since the last oil change, 20K miles?