Here's the best i can do with an ECU reset (I have a 166, my girl has a GTV):
o Disconnect battery either leave for ages or short the disconnected leads to discharge any residual charge.
o Reconnect battery.
o Turn ignition on but don't start engine, leave for 90 secs - inlet throttle body will be whirring and clicking to self adjust/trim.
o Turn off for 90 secs.
o Start engine but don't touch throttle, leave until engine warms up to normal (fans come on).
o Turn off.
o Start engine and go for an enthusiastic spin.
Let me know if it helps! GTV still mis-firing at 3K.