Help with Idle

[fastcar01]

Car is a 1992 Talon TSI Turbo. It was running awesome till the other day, it stopped idleing good. When you first start the car in the morning when it is cold the idle is around 1000-1100, but once you drive it right down to 500. When it is idleing with no accesories on it is around 700, but once you put it in drive, down to 500. I went through all the faqs and here is what I did so far:

1) checked resistance in IAC, 4-5 was bad, ordered new idle motor, installed, no better (checked resistance on new motor, it is good).

2) turned car on and off, listened for IAC, I hear it moving when ignition is toggled.

3) Reset IAC, by turning car to on and unplugging it then plugging it back it, no better

4) Reset ECU by unplugging fuse, no better

5) tested TPS with Ohm Meter, works fine

6) tested idle switch with meter, works fine.

7) the only other thing I can find is the BISS screw, which I just turned out a turn and the idle went up, then the idle motor brings it back down after a few minutes. Now I did not ground the two pins I need to adjust the BISS, but I am wondering if this could actually fix it, from what I understand, grounding the pins simply puts the IAC in the middle, so it seems once I put it back in operation wouldn't it just bring my idle down again?

Any leads would be appreciated.
Thanks

 

[herm1357]

them symtoms are also a sign of your ecu going on its way out

 

[karbon]

Linked from idle surge sticky.
Check the rest of these on here: http://www.dsm.org/how-tos/tttt/tttt3.html
Also just for fun, check the capacitors in your ECU for any signs of corrosion. It'd be a good idea to fill out your vehicle profile too.
Also take your BISS out and check the o-ring on there. If it's worn, replace it.