I guess it's just the opposite problem the other guy had.

After 58 mm throttle body install, it idles fine.

But, sometimes when coming to a stop, the idle drops well below the set 900 rpm and will almost stall. It slowly comes back up to the set idle.

Can I adjust the iac follower vs rpm to fix this?

Thanks,

 

I would also like to know this. I have the same problem after my LE2 cam install and MadWolf tuning.
Thanks,
Kory

 

Yep, sounds like the IAC valve is not open enough when the throttle blades are suddenly closed not allowing enough air to bypass the TB to keep the motor running. Can also trying opening the TB adjustment screw some as long as it doesn't effect the idle too much...making it too high.

 

Is that a different adjustment than IAC valve adjustment for normal idle?

Gary

 

Same adjustment screw. AS you turn the adj screw clockwise, it opens the throttle blades more when the pedal is at rest, by doing this, it allows more air to bypass..this in turn causes the IAC valve to adjust accordingly to maintain the target idle rpm..careful though as you cannot just open up the tb too much because you do not wnat the IAC to be bottomed out either..all the way closed...because then the ECM will have no control over how much air is bypassing the tb at idle to control rpms. Optimally you want the IAC step counts to be around 10-20 at idle...some say below 40 is ok but my experience has indicated it is best in that rangle of 10-20 so that there is crisp throttle response and no "tip-in" stumble.
Now, having the adj screw backed all the way out means when you let off the throttle, the blades close completely only leaving what air can pass thru the IAC valve to keep the motor running...this can cause the motor to shut off due to lack of air or idle iradically for a few seconds after letting off the throttle before the IAC can open enough to keep the rpms up. There are also some tables to control how far the IAC is open based on TPS or rpm..can't remeber exactly which..but it s IAC follower table so the IAC open steps vary with rpm/tps that can also be adjusted but I have never had to mess with that table.

 

The problem seems to be getting better as time goes on. Maybe the computer is learning, I don't know. If it doesn't get better, perhaps opening the throttle blades is in order.

One thing for sure, the problem doesn't occur when it's first started and in open loop.

And Rob, thanks for the info. Man, you have a killer garage! All's i got is a one car garage. The AC unit for the house and the water heater are in there too just to make things worse.