I have the same issue but mine is with the carb. I use Edelbrock's and the one I had on was fine.
It would run idle in 1st with no bucking. Just creeping along. Like it should.
That carb fouled with some trash and I got another same carb and it bucked. I am waiting on
that original carb to be gone thru so I can put it back on.
Seems there is a port on the bottom side of the carb that if exposed enough will cause that bucking and lurching.
When the idle screw is adjusted to a point that port is exposed. Try raising your idle.
