Perhaps a clogged fuel filter.
i work at a transmission shop i see these all the time it is an oxygen sensor. they can be expensive so be prepared
I have a 2001 Focus with 209,000 miles and it is still running well.
Check your Plugs and coils
all controlled by computer,see dealer for diagnostics
Could be sucking air into intake.
If you are getting a Lean code then it is probably being caused by the intake plennum gaskets. This is a common problem on the Windstar. The fix is relatively easy.
It will tell you on the stick, either "check hot" or "check cold", running or not.
Check the spark plugs and wires Do a compression test
running lean. too many possibilities to narrow down
That code is telling you that bank two is running too lean. For some reason the fuel mixture is too lean. Possibly an o2 sensor is malfunctioning.
what kind of gasoline are you running? and what color is the smoke?
sounds like the motor is running lean, not enough fuel.