Do you use a 1G TB? I know on the 1G you need to adjust the position of the closed throttle switch. I know on a 2G it's incorporated into the TPS, but I know nothing more of it. If the throttle plate is a little off-place in the shaft, it may be letting too much air around it. I'd think there is some adjustment with the closed throttle position sensor, but again, no clue. Is the throttle cable right? It should have some slack.

I just edited the original post to include this info, but I have a 1g n/t throttle body with 2g sensors. I was already thinking the throttle plate may be the issue. I'll take it off and take another look. The throttle cable is good. I don't know anything about a closed throttle position sensor. I'll look into it. Thanks.

If you are talking about it's low like on dsm link. All you have to do is adjust the BISS screw without grounding the connector i had the same issue but mine was high. If you talking about your idle is low then ground the connector and adjust the BISS screw if you check the faq theirs a a tutorial for it.

The closed idle switch is the sensor that contacts the throttle plate, and has one terminal on top of it. Just loosen the lock-nut, and back it out. The FSM procedure for adjustment says to use a VOM to check for continuity; after the switch closes it, turn it in 3/4 turn more, then fix the lock-nut. Then do the BISS procedure. With a rebuilt unit, you may want to play around with it some, instead of relying on the factory spec. of 3/4 turn. The FSM actually says 15/16 of a turn. I had to play around with it some myself, on my 2 rebuilt 1G TBs. Exact same issue. Just back-out the closed throttle sensor until you get your base-idle BISS setting where your ISC works good. Not rocket science. Your average stoner alcoholic (me) can figure it out.

jdiggity: I've determined the BISS is not the issue. I've adjusted it to its full capacity. It did help to adjust it, but there was not enough room to adjust it enough to bring my ISC position up to 30 prior to it bottoming out.

brownfinger: Ah. I knew about the sensor, just not the name. Thank you for clearing that up. I have indeed adjusted that as well. A concern I have now is whether or not my plate was re-installed perfectly on center. I have adjusted the closed idle switch sensor to the point that it will not let the throttle plate close any more. I plan to take the throttle body off, (again!), and test this. I'm hoping I'm right and I can fix the issue. I've been battling this sensor for over a month now!

Resolved: The problem was actually my o-ring. It was the wrong one. It was too thick and wasn't allowing the ISC motor to fully close.