HOT ROD CAMS HELP!

Sounds like an IAC problem

Sounds like an IAC problem to me. What have you done to diagnose this? Have you performed the basic IAC function tests? Have you altered the throttle body set screw? Do you have an ODB2 monitor/scanner?

Look at post #3.
http://www.stangnet.com/mustang-forums/810729-starts-but-dies-idle-help.html

Hanging idle is frequently a bad IAC or bad TPS. But with hot cams, this will reduce the engine vacuum. The IAC with the black vent needs engine vacuum to work. It may be possible that the vacuum is so low as to prevent it from working. In that case, consider switching to a later model IAC without the vent (2001+). However, it is way too soon to make that call.

FIRE IT UP:

If the engine has always done this since the cams and tune were installed then it is related to the tune. Your tuner should review the dashpot functions and scalars. If the hanging idle is a recent problem then you are correct to start hunting for a hardware problem.

I suggest that you call your tuner, collect a couple of datalogs that capture the hanging idle problem, and your tuner can e-mail you a modified tune to test. It may take a few datalog/test tune attempts before you get exactly what you want.

Chris