4 Wheel Drive/SUVs: 2001 Sport Trac starting problems, ford explorer sport trac, ford explorer sport

Question
I have a 2001 Ford Explorer Sport Trac. In the last couple months I have had intermittent starting problems. It will crank but won't turn over. I  do have an after market alarm system. The non starting has happened when using the remote start, when the weather is warm, when the weather is cold, when the truck has sat for awhile, when it has just been turned off. There is no particular situation that it happens with. I have tried changing keys. (trading keys with my husband) using remote start. Not using remote start. I have tried jiggling the key in the ignition. I have tried pushing on the emergency fuel shut off part. I had it at the mechanics for a week and of course it would not act up there. When it does start it runs great. It was recently tuned up. It has had the problem both before and after the tune up. Any help you can give would be greatly appreciated. Thanks Della

Answer
Della, first of all if it wouldnt start than it didnt need a tune up , becouse when it did run it ran good as you stated. I would say that it would most likely have to do with the security system that is on it. It is either shutting off the fuel supply or the igntion when it is active. So you might want to think about taking it to the place that installed that and have them check and make sure there is no wires bare , or loose on anything, that is usually the case. When you want it to act up it wont.... I would say that is most likely the cause though thanks alot and happy holidays ADAM