I followed Tom Keliher's advice in the "IAC and TPS Adjustment" tech article, but I couldn't drop the idle below ~550rpm. The IAC part of the article said to adjust it to 450, but below about 550rpm, it didn't matter how much I backed out the minimum idle adjuster screw.

Is this a mistake in the article, or should I be able to get it lower somehow? It seemed like he meant that w/o the IAC the idle should be lower than with it (assuming you're running in closed loop, in drive, I guess)...

 

bump, nobody cares to comment on this?? Is the question that dumb?

 

Stock eprom has a min idle set to 550rpm so you won't be able to get any lower. No way around it unless you program your own eproms. Add that to the list of reasons to do your own eproms!

 

That shouldn't matter when you're adjusting the min. air, because you will have the car in field service mode and the IAC unplugged. The ECM won't have any way to control the idle even if it wanted to. Once you plug the IAC back up, it will raise the idle up to where it should be.

 

Well duh, you should be able to get idle pretty darn low below 450 as long as the fuel delivery isn't running really rich.
Just thought I'd include a little section that shows the exact rpm the stock eproms idle at with and without A/c.