I have a 1998 ford windstar and mycheck engine light came on and the code was for the idle air control valve I replaced the valve and the reset the light but the light came right back on after driving a few miles then my transmiission would shift down ih to the first gear while I'm driving sometimes I can shift it to neutral and back to drive and it start shifting normally again something's it takes a while before it starts doing it and sometimes it won't do it at all what could be causing this

What would make my 1998 ford windstar just suddenly shift into first gear while I'm driving and then sometimes drive and shift gears right my idle air control valve went out and then all this started

The MAF Sensor is likely failing. It needs to be replaced or it will destroy the transmission. Stay away from remanufactured MAF Sensors--my experience has been awful. I would install a new Motorcraft part--these sensors are sophisticated and crucial.

If you want, check for codes/pending codes with an advanced scan tool. Don't overlook the possibility of a bad MAF Sensor connector. I've seen both the sensor and connector need replacing.

The MAF Sensor is likely failing. It needs to be replaced or it will destroy the transmission. Stay away from remanufactured MAF Sensors--my experience has been awful. I would install a new Motorcraft part--these sensors are sophisticated and crucial.

If you want, check for codes/pending codes with an advanced scan tool. Don't overlook the possibility of a bad MAF Sensor connector. I've seen both the sensor and connector need replacing.

Thank you what is a maf sensor and where is it located

The Mass Air Flow Sensor is located on the air intake. It will require a security Torx 20 bit to remove the screws. These sensors are very expensive--maybe even $300.

The Mass Air Flow Sensor is located on the air intake. It will require a security Torx 20 bit to remove the screws. These sensors are very expensive--maybe even $300.

Thank you very much for your advice I did what you said and it resolved my problem again thank you and God Bless YOU there should be more people like you around

Very nice job--you wasted no time whatsoever. From experience, I can say your situation can be a very difficult one to troubleshoot. You saved yourself a lot of money.

P.S. The automatic transmission is the weak link on Windstars. Every 30,000 miles, be sure to drop and clean the transmission pan and magnet, replace the filter, and refill with Mercon V ATF. You can increase the margin of safety by using Mobil 1 Synthetic ATF.