2000 Windstar engine shaking?
We saw something similar on our 1998 Ford Windstar where it idled very rough and actually died at a stop sign. There were no codes but a couple weeks later the check engine light came on while we were on the freeway for the intake manifold runner control. It turns out that the bellows on the IMRC's are connected to a vacuum line and can leak. In fact, both of my IMRC's eventually failed due to a leaky bellows.
Check for a vacuum leak with a smoke machine.
I'd check the cam timing first