You may try again. I`ve read your post about 10 times now looking for cryptic clues but alas its gibberish.
Well, you are right. Anyway, the car is an xk8, 1999. The reason for the coil change was that all the coils of the right side blown up. It happened after the car was washed. Then I send it for a full coil change. This new coils are the ones that are heating, they are obviously original coils. For the failures in the engine, it seems that some of the cilinders are not working, the engine has less power than I remember.I sort of get the feeling that English may not be your primary language! However, it would enable someone out here to help you if you could provide a little more information. It is always best to start by saying what car you have and what year it was built - there are many technical differences between the XK8 and the XKR and from year to year.
Why did you change the coils? It is not clear what is different about five coils you mentioned having changed all eight. I assume you mean that because they warm up without the engine running that they are all receiving electrical power of some sort.
What do you mean by 'notorious failures' when the engine starts? Has the MIL light on the dashboard lit up?
Unfortunately it is not possible to read the fault codes without a scanner. For many engine faults, a local garage with a decent scanner can often help. Without codes it can be a long process of guessing and trial and error to identify a failed component!