Deceleration valve leaking?

UPDATE>>>

I think I found the issue...bad F'n gas!

Removed everything associated with manifold vacuum: power brake, EGR, distributor, evap shutter, PCV, gulp valve...plugged them all and the thing ran the same, crappy. WTF, had kid keep the revs to 1200 and sprayed all the gaskets, no change. Finally bit the bullet and increased the idle speed 2 turns to 1200, got it to fast idle without pedal pressure and started shooting the carb with carb cleaner. Sputtered and cleared, again...sputtered and cleared......finally after about 3 minutes of crappy fast idle, the thing just settled in and started to idle smooth! Hey there....turned the idle down 2 turns to its original base idle and voila. Smooth 700 RPM idle. Started to add vacuum acccessories:
1. power brakes, no change.
2. distributor vacuum (changed for the better!)
3. PCV (clean now) no change!
4. Evap shutter...no change
5. Anti gulp valve---no change!

Verdict: The carb low speed air bleeds (?) varnished over due to non use and were plugged FUBAR. After carb cleaner opened them up, everything fell into place. Only thing I can think of as this happened once before on my original worn out carb. Sure felt like a vacuum leak as I had to feather the throttle just to keep it running like a leak would act. Im thinking the entire idle circuit was plugged up with this new shitty gas that doesn't age well. 2 turns took me out of idle circuit. Damn lawn mower acts the same: must be started every week or the bowl gets jello formed in it and main jet clogs.