It started about a month ago but then it sat when I went to start it again a ground wire from the back of the block to the firewall started smoking so I changed the wire and tried to start it and then the starter wasn’t engaging so I changed the starter now the truck is wanting to turn over but won’t so I added some new gas in the tank and sprayed some starting fluid in the throttle body intake and tried again it almost turned over but backfired. What am I missing or what can I do.