Re: misfire? 166 v6
First try a throttle body reset (no idle valve a its ly by wire)
- disconnect battery (make SURE you have radio/ICS code) leave for at least 30 mins to discharge ecu and/or briefly touch disconnected wires together to earth battery.
Reconnect - turn ignition on but don't start - leave for 90 secs - you'll hear throttle body whirr as it adjusts. Turn off, leave for 90 secs. start engine and let idle without touching throttle for at least 10 mins or until engine at 90degs/fan comes on.
Turn off. done.
If that doesn't do it , it may be either spark plug and/or coil pack. This can be checked by briefly removing the plug sequentially to each fuel injector (careful not to loose the spring clip). The one that has no change in idle locates your duff cylinder. Hope its at the front cos the back 3 plugs/packs are pig to change requiring most of a morning time wise and scraped knuckles!
Used coil packs £10 off ebay or scrappie.