Idle Hangs

[The3lite]

After installation of a full exhaust (LTs, Y pipe, Cat-Back) and a ported and polished throttle body, I have been having a wired idle issue:

If I am driving, push in the clutch, take it out of gear and roll, the rpms will drop to about 2k or so and it will slowly decrease until I stop rolling. Then the idle will return to normal. Also when shifting, the RPMs do not drop quickly so I end up waiting for the RPM to drop for rev matching on up-shifts. Any ideas on this one?

[MyFirstZ]

Did you tune it after and is the throttle body closing all the way. I had to adjust my FAST out of the box to get my idle correct, was allowing to much air where they had the set screw

[The3lite]

I have not tuned it yet. I thought that when it was ported and polished they set the idle screw to the right position. It seemed like it was closing all the way and the TPS sensor reads 0.

[NJ Torque]

TB may be hanging. See if you/someone else can look at a scantool while this happening to see if the TPS is hanging.

[The3lite]

Yeah I'll look at that. I looked at it breifly on dash command the other day and didn't see any issue. Probably not the safest thing to do while driving. Haha.

How can I tell if the throttle blade needs to be adjusted? Doesn't it need to hit the bottom bump stop before the blade hits the inside of the TB?

[xrelapse13]

most likely from the extra airflow unless they over ported the tb or wildly mis adjusted the idle screw although that's usually not touched.

The intake trims will adapt to a certain extent but a tune would 100% take care of it.

[Dave@EFX]

Who ported the throttle body?

[The3lite]

It was done by Potz Speed and Performance in Florida. Didn't come up with any bad information on them in my research.