My check engine light keeps coming on.

If your check engine light is on there should be stored codes in the control module. These codes can be accessed with a code reader or a scan tool. Please see the repairpal article regarding your check engine light for more information - http://repairpal.com/check-engine-light. I know of know reason a bad strut on your 1990 Ford Tempo would cause the check engine light to come on.

I had some wicked bad struts on mine and talked to a mechanic and asked him the same thing. He said that the check engine light wouldn't let you know that they are bad because it won't come on when there are mechanical problems with your suspension. That's just what he told me.

I have found on any number of instances that the individual failed to properly replace the fuel cap after purchasing fuel. A rule of thumb, turn it on and make it click at least 3 times. Next time the light comes on, check your fuel cap, you may just be surprised.