Join Date: Feb 2001
Location: The Sticks of Central TX
Re: Windstar rough idle and starting problem
Another thing that you may want to look at is the MAF for any contamination.
The MAF may or maynot give you an DTCs. But for lean driving sysmptoms that is another item to look at. The MAF can become contaminated and skew the transfer function so that the sensor over estimates air flow at idle and under estimates airflow at high airflow times causing the Fuel trims to learn the new bad corrections.
One thing you can try is to disconnect the MAF sensor connector. This will put the Van in FMEM mode. The air flow is inferred by using RPM and throttle position instead of reading from the MAF. If this cures the lean driving issues that you are having as described or all symptoms go away then the MAF sensor is more than likely contaminated and should be replaced. If they do not go away then there are other issues that can be addressed at that time.