Car Fail Issue

I have a real good one for someone to awsner.

Yesterday driving home I was on cruise control for about 20 min at 65 mph. Then it kicked me out of cruise and the RPM'S went to 4200 and rapidley went down with the speed until car died on side of road. After 10 min I got the truck started with no hesitation and drove off. I did not use cruise for a while. I drove back up to 70 no problem then went back to 65 and hit cruise then Set and as soon as I did same thing happend right after that. Now the car is completely dead and will not start. Im getting fuel. All parts are new from distributor cap all spark plugs wires. Radiator alternator, fuel pump, power steerting pump, a/c compressor, belts. Pully's. Everything pretty much. I did a full run up and down of the car and yet to find anything. I did a self check on my truck by holding down mileage and turning key and it runs a check of the computer in which nothing came back. It had half a tank of gas. I filled up on friday so it had a few days in their. However I did notice one thing that seems odd. Under the car next to tranny like right next to is a cable thats just hanging not to low but low enough to be like huh? It looks as though the male is in the female end of whatever it wwent to. However I have no idea what it could go to or if it goes to anything. Thats the only thing out of place on truck. All fluids are good. Nothing overheated. Tip top shape. So who can help me with this tricky situation? Please and thanks.