Ford Windstar Owner's Manual page 16

comes on and stays on when you are driving, have your vehicle
serviced as soon as possible. This indicates a possible problem
with one of the vehicle's emission control systems. You do not
need to have your vehicle towed in.
If the light turns on and off at one (1) second intervals while
you are driving the vehicle, it means that the engine is
misfiring. If this condition persists, damage could occur to the
engine or catalytic convertor. Have your vehicle serviced at the
first opportunity. You do not need to have your vehicle towed
in.
If the light turns on and off on rare occasions while you are
driving, it means that a malfunction occurred and the condition
corrected itself.
An example of a condition which corrects itself occurs when an
engine running out of fuel begins to misfire. In this case, the
Check Engine Warning Light may turn on and will then set a
Diagnostic Trouble Code indicating that the engine was
misfiring while the last of the fuel was being consumed. After
refueling, the Check Engine Warning Light will turn off after
the vehicle has completed three consecutive warm up cycles
without a misfire condition occurring. A warm up cycle consists
of engine start from a cold condition (engine at ambient
temperature) and running until the engine reaches normal
operating temperature.
On the fourth engine start up, the Check Engine Warning Light
will turn off as soon as the engine begins to crank. It is not
necessary to have the engine serviced.
Under certain conditions, the Service Engine Soon Light may
come on if the fuel cap is not properly installed. If the Service
Engine Soon Light comes on and you suspect that the fuel cap
is not properly installed, pull off the road as soon as it is safely
possible and turn off the engine. Remove and replace the cap,
making sure it is properly seated.
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