turboguard

So I just rebuilt my quadrajet using cliff's HP kit, and while it seemed to improve my throttle response and all around performance (I can actually squeak the tires from a dead stop and no more bogging!), I've developed an idle fluctuation when warmed up:


I also installed a brand new TPS and MCS as well.

The only other thing I changed were my spark plugs since they had fouled up pretty bad due to the carb running fairly rich before and also some oil leakage (replaced with NGK V-Power plugs)

What would be the most likely cause of this idle fluctuation? My carb didn't have it before I rebuilt it.

The only other thing that is odd about my quadrajet is my airhorn doesn't have a rich stop screw (as in there isn't even a hole there where it should go). My carb number is 17085204, which according to my resources SHOULD have the rich stop screw, so I'm thinking the carb is kind of a mish-mash from the PO. I still tried to set things the way they should be, but I don't have a dwell meter to exactly dial in my air bleed valve, so I just set it about 3 turns out (or about 1.7 inches from top to bottomed out plunger).

As always, I appreciate any input!

turboguard

It also sounds like a slight backfire through the exhaust (like a low thumping noise).

Could an exhaust leak cause these symptoms?