Idles better...?
It should barely idle in that case, I think. What year/mods?
It's a massively common issue. I've got it to where it is very drivable. Read every thread here and in Mustang forums. It's not vacuum, TPS is perfect, throttle plate exact, etc. Shifts great now at least, but that hang is about 4 second too long at idle. It may be I just don't drive her enough for ECU to learn. SPRING WILL FIX THAT.
You've applied a band aide for a bigger problem. Granted, that might be easier than actually fixing the issue, but it's a band aide nonetheless. And just FYI, the EEC will never learn idle without the IAC functional, so don't hold your breath on that.
I'm not implying anything. If your idle is hanging then you have excessive air entering the system. Fix that problem and the rest of it will also correct at the same time. You have a mechanical problem which is why I said band aide. Disconnecting the IAC does not solve the original problem and the EEC won't learn around a disconnected IAC. That's all I said and it's exactly what I meant.EEC, right! Band aide? It's a new IAC and still connected to harness. No intention of running disconnected, just asking what would happen for that reason. It you're implying tune ....
I'm not implying anything. If your idle is hanging then you have excessive air entering the system. Fix that problem and the rest of it will also correct at the same time. You have a mechanical problem which is why I said band aide. Disconnecting the IAC does not solve the original problem and the EEC won't learn around a disconnected IAC. That's all I said and it's exactly what I meant.
The aftermarket throttle body passes too much air around it's blade when closed. ... Stock TB's are best, BBK TB's are usually decent but not always, and MP throttle bodies are generally good, but Pro Prod throttle bodies are pretty much always poor in this department.
Every aftermarket TB I played with leaks massive amounts of air past the bearings on the throttle shaft. Have to modify them to add shaft seals to get the leakage to a point the IAC can do it’s job.