Since owning this Windstar I have found myself scratching my head a
few times. First there was the pinging (knock, or predetonation) that
seemed to happen on and off but not with any heavy load, but at slower
speeds, just driving around. This is very frustrating, and when I
searched I found that 1999 Ford Windstars are known for this issue
amongst the owners.
The other issue I had was the hard shifting into 2nd gear. This again
wasn't all the time and I noticed on hotter days it was worse or more
I am one of those people who like to figure things out, so I kept
trying and looking for an answer to these issues.
Being that I have a 1998 Ford E-250 super duty van, I knew that I
should be looking at the TPS (Throttle Position Sensor.) I learned that
this is basically a potentiometer that gives the computer the position
of the throttle (or your foot on the gas.) If you test it live - the car
in the on position, you can check the voltage and slowly move the
throttle. If it is good it will be consistently moving up or down in
voltage depending on how you are testing it. If it goes up and down then
back up again on your volt meter, then replace the TPS. Check it when it
is hot for best testing results, since heat adds to resistance
especially in warn electronics. If the TPS hasn't been changed in 50,000
miles, then chances are high it needs to be replaced.
So I replaced the TPS today and nice improvement on shift timing, and
acceleration. Here is the Throttle Position sensor on the 99 Ford
Windstar - Center of picture. This has three wires, if you remove that
plug you can use an ohm meter to test the TPS. (Trick to remove the
screws - turn clockwise first - not too far, just enough to break it
Something else to do in any car is
clean the MAF.
Usually a fairly simple thing to do, but you need to get some MAF
cleaner or some people use electrical part cleaner to do the job. This
will help make sure your car reads correctly the air flow. This picture
below shows the air filter case. The center piece, when removed is the
location of the MAF sensor.
Here is the DPFE which is for a later discussion....
Ford Windstar pinging -