Crank no start

Driving home from my girl's softball game my truck started to misfire real bad. Almost immediately check engine light came on and I was close to Autozone so I had them put it on the computer to save me time. Said misfire on number three bad coil pack. Well it has been my experience it is not always bad. So I lifted hood and sure enough someone had used the wrong screws at one point and it had shimmied out and coil pack was as far out as could go. I did not have any money on me and home was only about thirty away so I pushed it back down and drove home. Ran like a champ until right before my house when it loosened again. Got home grabbed a few different screws and got under hood found one to fit right tightened it down. Went to work next morning it ran so bad. Misfire jerking. I thought maybe I ruined plug so decided to change it. Could not get socket to go down for nothing. Took a little mirror seen I dropped screw in there and it was wedged good. Drove to Walmart (single mom from another state no other car) to get some long needle nose. Parked truck. Although missing like crazy it ran fine. Got back in to come home to fix it and it started. Idled real rough for about fifteen seconds turned off. Started again, three seconds shut off, third time it has done nothing but crank sense. I got the screw out, bought new battery. Speedometer and rpm's stay pegged 100% of the time even when battery disconnected.