My first problem solved.
When I tried to lubricate all the moving parts linkage to throttle, I found that the spring has torn-out, I change and it works !
I'm still don't have time to check the horn wiring as its to mess in the engine box, anyway I still can cope with the default one, so not a big problem for me.
Difficult to start, I'm sure what exactly the problem, I've put two bottles of fuel-injection cleaner and adjust the (vacum) by myself.
It seems improve as sometime it quite easy to start, but still sometimes it difficult (but not as previous).
Final one, what exactly could be made to reduce the harsh-shift-gear problem.My car always shift-gear harshly from 1-2 second gear, and from 4-3 (down-shift).
Thanks a lot for your kindest help.