Hello Im a newbie to this site. I recently bought 2000 Expedition XLT 5.4 with 166000 miles. So far it has ran good till Saturday morning it was raining and I started the truck with no problems. Ran it about 2 miles and it started to shake. kept on running it and got to moms house I parked in her drive way. Went out to the market and check engine light went on. When I drove back it did not shake anymore and check engine light went off. I scanned it it gave me cylinder 7 missfire. I decided to leave the truck in the drive way I got a ride back home In the morning I went back to moms house and my battery was dead. I thought it was weird I had an extra battery I replaced it turned it on with no problems a second later lights flickered and the starter engaged it did it twice. I turned off the truck left it off for a minute I started it again and same thing turned on fine and a second later the starter engaged again. I turned it off went in the house. A few hours later I came back out i turned it on and left it on for a about 30 min. And it seemed fine went back in the house an hour later I turned on the truck turned on fine 2 seconds later the starter started to engage and I turned it off waited a few min I started it again and a few seconds later it did the same thing the 3rd time I turned it on the starter engaged and stayed engaged I turned the key off and took it out but the starter wouldn't turn off I had to remove the battery post to turn the starter off. I tried to connect the battery back but the starter would engage with out putting the key in so I left the battery disconnected. My brother came out and asked me whats wrong I said I dont know he mention that early in the morning the starter was engaging I think thats why my battery was d ead. Any suggestions on what to check is appreciated I thinking my ignition switch went bad.