I had just replaced the IAC valve and since then I have been getting a loud whistleing sound. This seems to only happen on start up until the motor warms up. I am also noticing that on start up the vaccum on my air vents slam shut. Is this a vaccum pproblem starting? It also seems that I can hear alot more air being sucked through the intake. The truck seems to running really good I just want to catch any problems early.
Also can anyone tell me how to post pics. Every time I try says pics to big. Thanks

 

Sounds like you may have a vacuum leak from when you changed your IAC. I'm guessing it's in the TB area as well. Maybe one of the V8 guys can help you track it down as I'm not very familiar with the magnum V8s....they don't have enough cylinders

BTW, you can remove the Jet chip as well. It's not helping you