Its a couple year old Carter mechanical pump, I think its rated at 8 psi, but I don't have a gauge, I didn't think I would need one with a mechanical pump. The car has run fine in the past.

An erratic idle could caused by erratic fuel delivery, right? Maybe the pump is failing somehow.

How steady should the fuel level be in the sight glass when it's idling? It looks pretty steady to me, considering the car is vibrating as it idles.