Idles rough, even rougher in gear

Help! This is my work vehicle.

Pop is in pedal/ at pedal hard to describe, I can feel it in the pedal, when we got done with it I drove it about ten minutes then all this started.

Double checked firing order, note, then van was running fine before, just sluggish needed tuneup, the brakes were stiff and would be on the floor, but hold so I bled them now this.

Double checked firing order, note, then van was running fine before, just sluggish needed tuneup, the brakes were stiff and would b on the floor but hold so I bled them now this

Thank you will be checking TBI gasket soon as I get back.

Also, I cannot find a vacuum off the booster could the booster cause this? I think you may be right about the gaskets at TBI just wondering about booster, the van has been sitting for a couple years the first thing I did was replace the vacuum lines on top, then the next day the vacuum lines from gas tank to canister just fell out from under it and I replaced them and then yesterday doing the tuneup and bleeding brakes was the most work I have done to it and now I am where I am at with it. So, I am leaning toward the gaskets. Also when the van is running, push the pedal I can hear an electric whining sound comes from around the TBI cannot identify it cannot find EGR valve either there is a cylinder with a plug on the back side of it this sits where I have always known the EGR valve to be. I am trying to put everything out there on this as I am stumped.

Also once the van is running when I push the brake pedal down the engine stalls.

Also, once the van is running when I push the brake pedal down the engine stalls that is kind of why I keep bringing up the booster, I have got good pedal and it stops fine, but since bleeding the brakes the pedal is funny and van stalls when brake pedal is pushed.