Idle surging?

[Toronado]

Hi my 1978 elcamino with 305cid is surging at idle,
fuel pressure seems fine, checked float, both fuel filters.
Its a Carter 4 barrel 600 cfm in ok condition. It only surges at light acceleration and idle,
than it will idle real low like it is not getting enough fuel.  Surges from 600-800 rpms, new plugs, good wires they are all firing well, good fuel pressure. Doesnst seem to be the float, but it smell extra gassy, the problem occurred out of going over a speed bump to fast, any ideas?

[Toronado]

Oh ya adjusted the idle mixture screws which does effect the problem but doesn't eliminate it, maybe idle circuit, used carb cleaner no improvement..

[Cliff Ruggles]

What is the carburetor number?  What has been done to it?.....Cliff

[Toronado]

Not sure what has been done to it? As with most used carbs its does work but has plenty of issues- LOL.
I will get the carb number for you Cliff (it is similar to a old style Edelbrock no electric), I am pretty sure after several fuel pressure, and vacuum test it is the idle passage/circuit. as the carb works great with main jets flowing fuel, just idle is lack fuel, and it is intermitent problem, not a hot or cold symptom no fuel boiling, and float level is good, it is possible the float is getting stuck some how, time to dissasemble
Will post update soon....