Car Idles Better With Spout Out...why?

Make sure your timing is correct. Make sure the balancer isn't spun (if it is you can't set the timing).

Do you have any codes?

What SPOUT out timing does it idle well at? I have a 94GT with AODE and i ran it locked out at 24* for awhile - i thought it ran better that way. I have since gone back to running 8* base timing, but with computer control of the timing (I was not wild about not having timing pulled during shifts).

As wisely said by Rootus, really check out the balancer - otherwise your frame of reference is skewed.

Good luck.