changed oil, fill gas tank and now the worst surging and idle ever!

[HeadyFirebird'00]

i have just hit the 63000 mark and this surging idle is driving me bannanas! i was expecting to get smooth sails, but No. it tried the gas cleaner, nothing. it tried flooring it a couple several times to maybe clean some crap out, nothing. I do have a leak after the S pipe. tried to fix it(not siccessful), did all checks, pcv, plugs, wires, fuel f., air filter, everything i believe.
EGR could be my problem. I think my o2 sensors?
i dont know what the crap is causeing this surging idle. it surges like a pulse that last 3 or so seconds. this bites.
i dont exactly know what im asking help for, but i want some people to know that this idle problem my be inevitable or something.

[HeadyFirebird'00]

i get no codes about any emmission device. or any codes for that matter.

[Dr Todd]

Since you have no codes maybe try this:
Remove the rubber bellows from the throttle body.
With the engine turned off look back into the throttle body and see if there is a dirty build up in the inside or on the throttle plate. Move the throttle plate open and shut, or have someone on the inside of the car press down on the gas pedel. If you notice a large black build up, us a spray throttle body cleaner and follow the directons on the can.

DRTodd