Engine 2001 Mustang Bullitt Starting Problem

Just wondering. Are you interested in learning HOW to fix your own car? Or are you just interested in "parts changing" into a possible solution?

If looking for how to fix your car, then TEST to see if the IAC has what it needs to work? For example key on +12 volts at the IAC? Or testing to see that the PCM is actually in control the IAC before replacing what may be a good IAC. One way to test is to use a test light across the IAC. A working IAC should vary the brightness of the test light as the PCM opens/closes the IAC.

Or use an ODB2 scanner to compare the voltage as reported by the PCM to what is actually measured across the IAC.

If just looking to change the IAC without testing, the IAC can be found at the end of the tube with the square box.

Here's some information to get started on trouble shooting like a pro.

Troubleshoot IAC idle problems 1996-2004

ForScan ODB2 scanner w ELM327 USB

1996+ Crank with no start check list

@Netiis Did the person who told you what the problem could be do any dataloging? I assume they are just giving you their opinion of what could be wrong. Just to let you know without dataloging you will be chasing your tail replacing parts without knowing what the actual issue is. So if you have lots of money to waste start replacing everything people tell you to replace. Maybe you might hit that needle in the haystack by luck. The issue your having can be alot of different issues. Anything that is related to spark, fuel, and air, which is almost every componant on your car. There is only two ways to identify your issue. Take it to a mechanic which will datalog it to find the issue or datalog it yourself. Option 3 start throwing money and parts at it.

And if this was my project car, with that many miles, I'd replace all spark plugs, coils, injectors, oxygen sensors and give it a good oil change. Then go from there diagnosing any issues you may have. But that's just me.