Dennis MacGyver wrote:
Pop the CAC hose off, look in and see if the FCV butterfly is in total horizontal (open) position. That's the position it should be in with the engine off AND the motor running. It only closes when the motor shuts down and then only briefly. The spring mechanism in it holds it open, so if the little motor on it fails, the return spring will make it return to the open position.
I wish that was the only time the stupid FCV closes, but it isn't. If the computer's nanny system doesn't detect a large enough amount of engine-killing soot being redirected back into the intake from the EGR, it will command the FCV to choke off the intake to force even more suction on the filth-line.
This is why unplugging the MAF sensor is desired - it removes the computer's ability to detect EGR flow, which cancels the computer from even attempting to use the EGR (and conversely) the FCV to increase the flow.
Anytime you are not at WOT, you are at risk of the EGR system activating and closing the FCV - the factory program uses the EGR ALL THE TIME (I seem to recall something like 80-90% egr use) which is partly why they fail after only about 20k miles in service.
It is a distinct possibility that the constant smoking is because your EGR has failed partly open or is stuck open with soot, and you are loosing boost into the exhaust as well as overfueling because of the computer expecting a certain boost amount, and not getting it.
Please note: ALL this information applies to 2005 / 2006 2.8L CRD motors, and any that are the same design... I don't know how the earlier 2.5L engine differs.