There is a strong smell of fuel. Restart and tries to start on one cylinder then eventually starts as above then whilst driving it stutters (power loss) then clears. Fuel mileage is down. Sometimes we operate normally for days. Isn't affected by weather/temp. Computer diagnosis says all four coils down (nonsense). Engine management light is on permanently.
As it happens I have fixed it! The codes are irrelevant, I did it the old fashioned way l.O.L.
There was information I was not made aware of. I started the car (no problem0 and whilst I waited for the engine to warm up I put the heater on max. As the engine warmed, the heater remained ice cold. I rotated the control from hot to cold then the heater came hot - then went cold again (all the while the gauge showed hot) - NO WATER IN COOLING SYSTEM!) I checked and found this to be the case, req'd 2litres to fill up - apparently the heater had been playing-up for some months! Having filled up and bled I took it for a spin and got the computer re-set EVERYTHING A.O.K.
The problem being that the engine coolant temperature sensor was telling the ECM that the engine needed more fuel for cold running!
So much for onboard diagnostics! Garage said "you learn something new every day"
Given that there are NO obvious signs of a leak and the garage gave it a full service a couple of months ago, it wasn't a very full service eh?
Mechanics? My Arse.
Thanks again for your help, and hope this helps someone else