Hello.
SORRY for my English, it`s very difficult to write auto terms.
Ok.. My car is festiva 91 with b3 carbed engine. Unfortunately I have some problems with this engine. Sometimes idling vanishes in the engine.
it`s possible to drive all the day, and then get stuck on a red light. And i can`t start the engine. Very often rpm fall to 0 after warming up. On idle works roughly. First thought that it`s the carburettor does not work fine, but after numerous cleaning and tuning this version has gone.
Then thought, that is problem in ignition system. Have diagnosed by an oscillograph: the coil, a winding, signals from the switchboard (commutator, sorry I don`t know how it`s on English, located inside the distributor, with 4 contacts, 2 or more are connected with the coil), all works! What should i do? What is the problem? And this problem isn't constant, appears, disappears
There are 2 photo
Carb

Engine

There are other
photo
I sprayed a liquid for clearing the carburettor and have noticed that the idle began to normal. Now I think that problem in vacuum tubes, or the valve of additional submission of air (stuck in the open position). But how them precisely to check up? I think can throw out this carburettor and put something easier, without vacuum. Any ideas???. Help...