Engine dies when slowing down

Friend has a 93 Ford Taurus. Sometimes when she has to quickly slow down or come to a quick stop the engine just dies. So far is has restarted ok, but we are affraid that one day it will not.



Any ideas what we could try to do to troubleshoot? Thanks in advance for any help.

First, do cheap stuff. Cheap stuff: Use MAF Cleaner on the Mass Air Flow Sensor (carefully). Use a Throttle Body Cleaner to clean the throttle plate and bore, and the Idle Air Bypass Valve air passages (and pintle).
The following article tell how to electrically test an Idle Air Bypass valve. If cleaning doesn’t help, it may be more economical to replace the Idle Air Bypass valve: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800635b8
Recent spark plugs and air filter?

It could be that the torque converter is not unlocking. You might be able to unplug the connector that controls TC lockup and prevent the lock. If the problem goes away, you know what is causing it.

1993 Ford Taurus? The #1 suspect for this problem is a lazy Idle Air Control motor.

Tester