Od and check engine light stays on

I would suspect the VSS - vehicle speed sensor is going bad . The C.C. to work needs a speed input an the shift points are also speed related ,plus some other thing's . To know for sure a qualified tech should hook of a factory or some other type professional scantool that can view sensor data parameters ,while driving the vehicle . Not auto zone scan .

fuel pump? it is running lean (not enough fuel) or a leak in evap

well check engine light is most likely a sensor and needs to be scanned and that could caose the overdrive problem

Check your Back pressure valve. The hose on the top of the EGR runs to the backpressure valve loated on the firewall of your car. Also check the mass air flow sensor. There are plenty of times when the EGR code pops up that something else is wrong with that system

Most likely you have a bad COP (Coil On Plug) .
Maybe more than one. Very common ford problem for last 12 years.
If you get a MIL Light on the dash (the wrench),check for a PO300 Code.
A PO304 would be coil #4,PO306 #6 Etc.
Cyl 1 thru 4 on pass side
Cyl 5 thru 8 on driver side,front to back

Also hills cause a hi engine vacuum and thus a possible EGR Valve going bad. You can unplug the vacuum lines and plug, to diagnose that issue.

Also leave the EGR disconnected if your working on coil issues. Just note the MIL light will stay on all the time,and remember to check your 300 codes if you feel a hesitaton or miss.

You can take the van to Autozone, they will test the check engine light to be sure. More than likely you have a bad plug wire or plug. If a plug is not firing right it will not burn the gas, hence your rough idle and back fire.

Go to your local big chain auto store and ask them to scan the codes. This will get you going the right direction.

I had the same EXACT problem on my 2002 Sable. Freaked out thinking I needed a transmission.
All I needed was a tune-up. When not firing properly, sensors "take over" to compensate.

Check plugs/wires...you'll be surprised...I sure was!!

Many people never think about or ask about their exhaust sytems causing problems..a bad catalytic convertor can cacuse exactly what you're talking about..

A very simple check to see if that's your rpoblem

have someone scan it for transmission codes. Most likely it is your Torque Converter that is going out, but it could be a solenoid, What color was your fluid?