Looks like the weber 34dgec sold to fit the 258ci by Weber North America.
Some one saved $80 over buying a Genuine Weber but they are apparently not very good.
As to your flat spot, it could be a faulty or blocked accelerator circuit. When you have the filter off and pump the throttle do you see a nice spurt of fuel?
BagusJeep lives in Bali, the Land of Temples.
With a Jeep every prayer counts.
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1995 Cherokee 4.0 - CHEROKEE