I have a 2003 Windstar, 3.8L with 93000 miles. August 2012, I was experiencing hard shifts and was advised to get a transmission service done. I took it in, only to find a few days later that the tech overfilled the trans. We were driving on the highway and started smoking. After a short time, it was fine and shifted normally. Later that same week, we started the van in the rain and it was running so rough we could barely keep it going. Husband replaced plugs, wires and coil pack. Fast forward to May 2013. Van was driving fine all day then suddenly starts running rough. We find one plug wire barely on coil and one completely off. Beginning of September the rough running returns. Check wires, fine. At beginning of problem it was a stutter that got increasingly worse. Then it progressed to a jerk and hard shutter. This happened at any speed, warm or cold engine, wet or dry conditions. No check engine light. Replaced fuel pump(looked worn, but not shot) with no change. Replaced fuel pressure regulator(was bad) and van had increased power but still shuddering bad. Put in fuel injector cleaner with no change for almost 2 weeks. Then suddenly ran fine. In the meantime, we had a sudden tear in a lower coolant hose which we found a week later was caused by a trans cooler line leaking fluid on the coolant hose. Added a quart of fluid and it came up to normal level. Few days later, the level is once again low(no surprise leak not fixed yet) and the trans suddenly started shifting from 1st to 2nd late. RPMs go up, no shift, ease off throttle it shifts. This repeats throughout drive. Reverse is fine. Rough running has returned also.
Is there a connection between two problems or are they separate things?
Could this be TPS?
We are on tight budget and have just finished fixing the husbands work car and don't have much left to fix this one. This is the get the kids to school and shopping Mom mobile.

 

Have you done anything to the vehicle yet?

 

As far as the transmission, no. As far as the running, we have replaced the fuel pump, fuel pressure regulator, and run Techron through the system. Last year, there was new plugs, wires, and coil pack.

Wondering if the two problems are related. This van has been a nightmare this year. We bought it used at a good price March 2012 with low mileage. In the past year, we have done the tune up, front bearings(both sides), one transmission line repair, front brakes, and a lower coolant line. Now in past week there is a new transmission line leak and this problem with shifting.

 

When the wires were replaced, may I ask who replaced them and where were they purchased ?
The reason I ask these questions is some aftermarket wires (not Motorcraft) are manufactured differently from original equip and are much more susceptible to misfire problems. The other thing is when the wires are run parallel to one another one can induce a spark in the other and now the wrong cylinder(s) are firing and this appears as rough running etc. The fact that some of the wires came out of the tower means either they were not installed properly, were poor quality or a possible coil problem.
None of the above could be responsible for the problems your vehicle is showing , but the engine must be performing properly before any trans diagnosis should be attempted.