1996 Windstar Gl From Hell

Help! This is my First Time Posting. My Wife Drives This Van With My 2 Small Kids. We Live In A Very Rural Area With No Cell Phone Service And I Am Getting Nervous.
There Is No Rhyme Or Reason As To When This Occurs. While Driving, The Van's Rpms Will All Of A Sudden Go Up And Down, Up And Down. Sometimes The Rpms Will Go Up And Peg Between 3500 And 4500 Rpm. While This Is Going On The Van Starts To Buck A Little. It Almost Feels Like It Has Downshifted. This Seems To Occur Only After The Van Has Been Started And Stopped A Few Times (while Doing Errands, Etc.). If The Van Is Driven Without Starting And Stopping It Seems To Not Happen.
Also The Speedo Is Bouncing Around Like Crazy.
Our Local Mechanic Can't Seem To Figure It Out. We Have Done A Complete Tune Up With New Wires, Etc. We Have Changed The Coil, Checked For Vacuum Leaks. Ther Are No Engine Codes Coming Up On The Computer. As For The Speedo He Says We Need A New Sending Unit, But I Always Thought That They Rarely Went Bad. Could It Be Something Else?
Any Help Out There Would Be Greatly Appreciated. We Are Struggling Farmers And Can't Afford A New Vehicle.

My '99 exhibited a lot of craziness..including random tranny shuddering, etc. I finally found a worn spot that was grounding the drivetrain harness where it was routed against the firewall. Had to remove the wiper arms and plastic cowling to get to the area.

You might want to thouroughly inspect all the harness under-hood.

Phoneix

I would look at the TPS (Throttle Position Sensor). This sensor tells the computer how much the gas pedel is being pushed thus controling the engine speed.

As for your speedo, ...I'm not sure if Ford went to electronic speedos in 96. (My 95 Windstar is cable driven). Your Vehical Speed Sensor (VSS) may be going out. If the VSS is going out the tranny be be shifting poorly.?? The VSS is located in the back of the engine/tranny just under the exhaust manifold. A real pain to get at.

Reagards

Dan

Good call, Dan. A worn TPS can indeed send erronious signals and cause these symptoms.

If you have the mechanical gauges (not digital)....you have a mechanical speedo.
I have a '96 GL....and my speedo has sometimes been noisy....and for a while...kinda wandered around......The speedometer can cause this....the cable can cause this...as well as the sending unit.
If you can hear the speedo making a noise when it is acting up....I would suspect the speedo....and they do fail. But the other 2 items can cause this as well.

The following link will get you to some pics of my '96 3.8L.....

http://community.webshots.com/album/201931518cScpNK

Select "96 3.8L Windstar"
I have indicated the location of some items.....Including the Throttle Position Sensor (TPS) and the Idle Air Control (IAC).
The IAC is also known to fail....usually causes problems with the idle speed. The IAC takes over control of the engine speed (with commands from the computer) when your foot is OFF the accelerator.
Just under the picture title.....there is a little "view full size" icon....that you can click to blow the image up and see more detail.

You may also want to check the transmission range selector switch. This is nothing more than a resistor divider that is mechanically linked to the gearshift and is mounted on the top of the transaxle. When you move the gearshift, a different tap on the resistor divider is selected which is sensed by the computer to determine which gear you are in. If the computer gets faulty info from this switch, it may try to tell the transmission to go into an undesired gear.

My '96 would intermittently downshift to 2nd and then back. Naturally, the rpm's would jump when it downshifted. It would happen every couple of days but finally got to where it happened all of the time. Cost of the switch from Ford is around $60.00 US. A local transmission shop found the problem using their OBD diagnostic tool. Via OBD, the computer was indicating that it was asking the transmission to be in 2nd gear no matter where the gearshift was actually placed.

Don't worry these vans are only a piece of shit. Yours is doing fine MY 96 has some problems worse than that. Mine has 125,668 miles on it and it has been through 3 engines (damn head gaskets) and about 6 transmissions and i drive this damn thing like grandma. all i have to say is PHUCK THESE VANS!!!

Very descriptive Stoned_pimp but not very useful information.

I find it very hard to imagine (read believe) that one could possibly go through 3 engines and 6 transmisions if one was properly looking after the vehicle and having the work done by competant personnel. Perhaps grandma is doing the repairs too. In fact weren't you the one that had troubles with all of the vehicles you have ever owned regardless of make or model? Kind of makes you thin the problems may not be the cars.