Hard to say without physically being with the car and experiencing the problem.Lo & Slo_Bunny wrote:I will try to check if there is leak by the manifolds. But anyway do you think the carb might be a problem
Keep on fault finding. It will take time and be difficult at times, but you will be able to work it out eventually.
Start at the basics and don't overlook even seemingly simple things, the most basic stuff can cause huge headaches.
Lastly get solid information and measure as much as you can, it will help isolate the issue to one area. What I mean is do testing of each component of a system in order to eliminate it. Even unrelated things may be involved.
Take this as an example, during the 90's there was a batch of Citi's that had faulty fuel tank ventilation, causing a fuel starvation problem and in extreme cases badly damaged fuel tanks. How it was identified was by driving a short distance and opening the fuel cap. If it sucked in air it meant it wasn't equalising the air pressure inside it with the atmosphere. In short it could build up enough negative pressure inside the tank to make the fuel pump unable to draw fuel from the tank. The car would run out of fuel and the guage said plenty. The final solution was to drill a small hole just inside the top of the filler neck.
Try driving the car without the fuel cap for a bit and see if your problem persists. I'm not sure if this is your problem, but its worth a try.