Please Help 1998 Svt Cobra That Will Not Run

[Dbain92]

I have a 1998 SVT Cobra that will not run. To start off with I drove it the hole day before and it never missed a lick, I got up the next morning tried to start it and nothing I thought maybe someone bumped it over night and shut the fuel pump down checked the inersha switch it was still on fuel pump running fine so I tried a new fuel filter still nothing after some trouble shooting I found that the car was only firing on 2 cylinders so I tried 2 new coil packs plug wires and plugs and a new cam shaft sensor and crankshaft sensor after working on the parts for a few days I got it started 1 time and it sounded like crap missing and a rattling sound for about 5 sec then shut back down never to start again I was debating on a new control board or getting it re flashed but I had also seen some blogs about the security system locking the car out and bad timeing chain tensioners causing the motor to get off timing so I didn't know if that could be an underlying issue. I have since gave up for about a year out of aggravation I'm good with mustangs but this has got me beat to the max so anyone with knowledge of these issues or even some advice on where to turn to next would be greatly appreciated thanks.