2001 gt starting problems

I have a 2001 gt mustang with 84,000 miles. The problem I am having is the car is turning over but doesn't start. The fuel pump is coming on and I have fuel pressure. I changed the computer out with a brand new one and it is still doing the same thing. I changed the wiring harness because I thought it was bad because sometimes I could move the computer around and it would start. I did get the car running after changing the wiring but when I cut it back off and tried to restart it, it wouldn't start. If anyone has any suggestions or has experience similar issues please help me....

This is where it started. When I first got the car it was having this problem. Every time somebody got out the passenger side of the car and closed the door the car would shut off , but it would start right back up . So I took it back to the dealer and showed them what was going on and they keep it in the shop for a month . When I got it back they said they had to change the computer and fix the wiring harness so it done fine for about 2 years then I started having the problem again . So this time the car sat for about 6 months I had the computer siting over in the floorboard and one of my friends came by and was looking at it, he seen that one of the wires going to the computer was crimped so he straited it out and the car ran for about a year like that. Then I hit a deer and had to put the computer back in the kick panel before state farm came to look at it and it hasn't ran since so I got a wiring harness thinking thats got to be the problem since the dealership fixed one of the wires on it and buddy straited that wire out and it ran fine . I didnt just go and buy a bunch of parts to see if they would work.