I think I have nailed my lumpy running when hot.
It would appear that one of the injectors stops working - it seems to kick in and out.
I unpluged the injector when it is runnig rough and on No2 cylinder it didin't make any diffrence When it is not running the afr is about 17. When the injector starts the AFR goes back to 14.8.

I have checked the wiring to the injector with a noid light and it seems to be pulsing ok.

Anyone else had this - I reckon it is the injector?
Cheers

Frank

Can you swap injectors over to see if the problem moves too? That would prove once and for all it was the injector and not plug/wiring etc breaking down..

It's possible to get injectors cleaned on an ASNU machine but it may be worth changing the injector to be on the safe side

The injectors can get blocked by dirt very easily. You can send them away to be cleaned, but I did my own; dunk the nozzle end of the injector in an ultrasonic cleaner and run for a couple of minutes; remove; rig up a 12v supply to open the injector and blow compressed air through it. If you aim the spray at a piece of kitchen towel you may capture any dirt that's blown out.