1998 Ford Explorer truck cranks but as soon as you give it

Truck was running fine until I took out dashboard to replace some lights and when I put dash back in I crank it andit wasnot idling good as it was cold ( 29 degrees Out ) so I gave it somegas and it shut off. I try to recrank and would not strart.I let it sit over night and was able to crank it but as soon as I gave it gas it shut off. I do know who had before me had bored out the Cat converters but I was able to drive fromCharleston SC to Beaufort SC with no problems. Also when I crank it the next day I had pull out the fuelpump relay and did not put back in and it crank but as I gave it gas it shut off