Weird RPM problem

[Foxone]

I picked up a 2001 Corolla with 84000 miles on it. Been tinkering with it, got my CEL lights taken care of. But now whenever I fill my gas tank up (No overfill) and Im idling, my RPM's go up and down almost to the point of stalling. Then after about 2 miles of driving, back to normal.

Things Ive replaced:
Entire charcoal canister
Check valve and gasket on top of gas tank
New plugs
New o2 sensors (Both)

When I got the o2's, they were Denso universals. Where you have to splice your wires, now those are two black, blue and white. What would happen if the two blacks were somehow reversed?

Thanks for any help guys.

[viper_cole]

normally the o2's don't work until the engine warms up, until then its in a open loop mode once it warms up the o2 sensors go into closed loop.

have you tried this with only filling to approx half tank?

the 4 wire o2's are heated o2 sensors and usually the black wires are grounds and unless your circuit is a ground switched circuit it wont make a differenace

have you tried cleaning your sensors (MAF, IAT, MAP) and the IAC (passage) and throttle body?

[Foxone]

The car was warm at that point. Ive cleaned every thing I possibly can find, maybe I missed something, Ill have to try it at half tank to see.