Please help! My 1999 discovery 1 is misfiring. It throws these codes: p1314, p1316, p1374 and p1375. I just changed the plugs and it has fairly new wires, also just had the fuel injectors cleaned. I don't know what to do next. I am in Oregon

 

If the truck was running reasonably well before you did the work you described the very first thing I'd check is the wire routing. If it was not, tell us more about that.