When I attempt to adjust the idle to anything below 1500 rpm, the throttle pulses (for lack of a better term). It pulses from 1000 to 1500 or so.

 

did you check and adjust the TPS?

 

mine pulsed very similer, got rid of any chance of a vaccum leak, made sure everything on the TB was smmoth and working right, swaped ecu's, swaped tps and adjusted, and after it warms up and at idle every ~15 mins the rpm needle will sloly start to move up and down progressivly getting to ~500 then progresivly less till it stops. it doesnt sound to me to be any grounding problem so im gettin a brand new tps, ~bac, and find a few ecus to try.

 

im asuming that it was fixed. what did you do to correct the problem? id like to know because my problem is similar.

 

Still working on it. Planning on getting the injectors cleaned.