318 Engine stumble

I’ve been messing with this again. The problem is still there.

The only thing to concentrate on is pulling the throttle to right off idle position and holding it there.

THe transfer slots are going full force. I can look down and see them working. The engine is stumbling here. They are air and fuel. A fine spray.

The accelerator pump would not be doing anything.
The power valve would not be engaged because
........The engine is held by me to a position of right off idle.
The only circuit that would be working is the transfer circuit because the accelerator pump has done its job.

Where could extra air be coming in. The vaccum ports are all blocked off.

Could it come into the intake or
.....power brake booster connected straight to the intake.
Pulling in extra air as the throttle opens up and air velocity is increased.

If that’s the case. Wouldn’t idle vacuum be really low. 21” is a pretty high number.

It seems like this problem is extra air coming inrifht off idle into the transfer circuit .
It might be masked at idle by tuning it out and pulling enough gas at higher rpm to mask it there as well.


Could an intake leak cause a problem like this?