car wont start

my friend has a 93 ford taurus SHO and every now and then it just wont start it only happons if we go for a cruise up to the local walmart and we go in and when we go back to leave the car wont start its like the starter wont even engage does anyone have any sugjestions on what it could be cause this to happon

put a new starter in it.... the magnetic pieces in the starter are no longer engagingDO it right, Don't use SONY

it will start but it has to sit for like an hour before it will start agian

I had a 82 Ford Escort that did the same thing. It would start fine when the engine was cold (after sitting for an hour or more) or hot (had been shut down in the past few minutes), but wouldn't start when it was "warm". Turned out to be a starter module or some crap like that. NOT the starter or attached to it, this thing had wire harnesses attached to it. This thing was a square aluminum looking box on the visible side and the back side looked like it had sand inside and sealed with a transparent yellowish silicone material. It was located in the engine compartment toward the top on the cabin firewall. Don't know if that is what's wrong with this one, but it's something to look into if the starter is not faulty.