surging/bucking on acceleration

[gungadin]

Would anyone care to speculate why, when I'm gently accelerating the engine bucks and surges...you could say stumbles. But if I get into the accelerator substantially more it is smooth and powerful
Once I get up to speed it seems to hold a steady speed better.

'76 911S w/ '79 3.0L engine w/ points.

clues suggestions guesses all appreciated.

[tmalaret]

It may be rich. Does it happens always?

[magic930]

Check your timing and check for vaccum leaks.