Seljobeljo

I know it's an common subject but I've been thru them all and can't find a real problem.
And the problem is my car started rough idling a couple days ago, and it doesnt do it all the time, it does it randomly. When its his "rough time" he goes from about 400 to 900 rpm and it can turn off if I dont press the throttle. When it is happening I can hear loud knocks from fuel pump area (a few knocks every few seconds).
Also, the mixture is rich and I can feel the smell of gas.
​​​And i dont know could it somehow be related to all of this but at the same time my fuel gauge went crazy and its goin from empty to full and backwards all the time.
Thank you for the help