I am boosted with the saab setup and when I push the clutch in to slow down my rpm goes below 500 and then will even out at about 900.When I start the car or I am stopped and rev it up the idle is all way fine.Any help would be appreciated.
mine does that sometimes after i drive somewhere then go out and start it, i always give it a little gas so it wont do that

not sure how much a bad ground would affect it, but it seemed to do that bad when i grounded 3 things on the same bolt under the dash. not too keen on electrical stuff so i dont know how big of an issue that would be

12.33 @ 111.67 mph [Oct 2009]
Dyno'd on 08/02/09 - Mustang Dyno:
327.6 WHP 333.6 WTQ [10.1 AFR]