My Jag has been out of commission for the last ten days with non start problem. Engine light was on. Plugged in diagnostic to lap top and found fault code P1586, everything pointing to throttle position sensor, throttle body etc. What to do, get a new throttle body. No, I remembered just before fault occurred that I had switched some relays trying to get my cruise working. On examining relays discovered that four of them where damaged. replaced from ebay. and guess what, No 4 relay in engine bay fuse box was faulty. Engine now back to normal, thank goodness, for a few pounds and not a few hundred. Regards Stan.