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Jeff Niceswanger · 06-30-2021, 07:36 AM

Like previously stated, if the car has an IAC ( Idle Air Control) on it you can adjust the throttle follower and try to help it. But an active IAC on a Superstock car is rare. I doubt you have one. Most of them are unplugged, blocked off, gutted or deactivated in the program. Its probably just a ill tuned map with the tune needing much more air than it should to idle, so the throttle body blades are opened way up, which in turn causes a sloppy return....
Make sure you don't have any type of vacuum leaks, especially at the map sensor or hose. Vacuum leaks play havoc with FI tunes...
You didn't mention whether is does this right after its been started, of after its warmed up and siting there running. If its right after a restart it is the After Start Enrichment and Decay rate,. Probably more so the Decay rate.

06-30-2021, 07:36 AM	#3
Jeff Niceswanger Senior Member Join Date: Jul 2003 Posts: 894 Likes: 687 Liked 1,034 Times in 368 Posts	Re: Xfi 2.0 question on lt1 Like previously stated, if the car has an IAC ( Idle Air Control) on it you can adjust the throttle follower and try to help it. But an active IAC on a Superstock car is rare. I doubt you have one. Most of them are unplugged, blocked off, gutted or deactivated in the program. Its probably just a ill tuned map with the tune needing much more air than it should to idle, so the throttle body blades are opened way up, which in turn causes a sloppy return.... Make sure you don't have any type of vacuum leaks, especially at the map sensor or hose. Vacuum leaks play havoc with FI tunes... You didn't mention whether is does this right after its been started, of after its warmed up and siting there running. If its right after a restart it is the After Start Enrichment and Decay rate,. Probably more so the Decay rate. __________________ Jeff Niceswanger 3740 SS Last edited by Jeff Niceswanger; 06-30-2021 at 04:30 PM.