Won't start up, was running ok but sluggish

Prev owner backed up on a pole and run into another pole both on the driver side
I've fixed most of that. I have driven the truck around my place while working on it,found split in the intake hose replaced.
Unsure of mileage on cam belt so I replaced with the whole kit including crank pulley for timing belt
Cam and crank sensors coils,wires, and plugs
MAF Sensor, TPS, IAC Motor
Under dash wiring harness w/ fuse box
The veh.has run. Good off and on throughout all of this ,
last time It ran I filled the AC system
Installed a new stereo w rear and front camera and GPS
3 days it ran great then not
I replaced the computer because mine didn't turn on the check eng. Light
But it hasn't started up yet
I don't have the master key just copies
Any advice would be great thanks

Tim