New to this Mercury forum. Past owner of 2 1968 Mercury Cougars - how I wish they were the problem .

But, the problem I have is with my mother's car. It's a 1997 Mystique, 4 cylinder. It randomly decides to not start. It cranks just fine, but won't fire over. When it does start, it starts like nothing is wrong. I picked it up today and started it when I first got to her house. When we went to leave, it wouldn't start. After playing with it for about 20 minutes - pretty much just checking things over - it started up. The fuel filter is only about a year old with minimal driving (Mom's 79 years old ). I was thinking the fuel pump, but when I drove it home it acted fine. I floored it on a stretch of the road home and it never sputtered at all. When it did start, it almost acted like it HAD been out of gas. I turned it off when I got home and restarted it with no problem.

Anyone have any ideas where to start?

 

You should be able to hear the fuel pump working. Close the door, put the key in the ignition and turn it until all the warning lights come on but do not go all the way to start. You should hear the fuel pump, under the backseat behind the driver pumping away. Try it when you know it is working and listen. The next time it will not start, see if you hear the pump. I had my car sit for almost 8 months and it would not start either, pulled the pump out and sure enough. Banged on it and it started again. You could take a rubber hammer and bang on top of the floorboard or under the car by the pump to get it going but it is probably on the way out.

 

I would determine if it is spark or fuel. Check the fuel rail when it wont start and see if its charged(carefully) also check it for spark, note beware the auto shut down relay ASD