Hello,
its about 1 mount I bought great Audi A8 1995/12, 220Kw, Quattro.
Everything went well till friday 13th, yesterday... :-(
I have to change new termostat and after it when I wanted to start car, there were not-flashing alarm CAT on main display.
I started the car but after 5 seconds it missfire valves 1,4,5,8 (all OUTer valves) - I tried it by connecting and disconnecting cables for ignition coils. 1,4,5,8 were deatd after 5 seconds.
If You start car againg, everything is everytime OK, but after 5 seconds it goes only on 4 valves (all inner are OK).

I tried to swap main ignition coils but stil OUTer coils are death.

Can anybody help me..?

 

Try swapping your ignition control modules over. If the other four cylinders run instead then thats it. They are fitted back to back under the trim to the rear right of the engine compartment near the screen wash container. Just swap both pairs of plug on the modules with the other. I had one fail on me. Cost about £60 from Eurocar parts to replace.

 

Thnx, but this I did ---------------- " I tried to swap main ignition coils but stil OUTer coils are death."
Problem is after 5s when motor start missfire... :-(

 

It would seem that you have a blocked exhaust (maybe the cat melted or broke to pieces). Try undoing the screwsconnecting the manifold to the cats and then start the engine for a while and see if it helps.