My car cranks fine but won't start without holding down the gas sometimes. It happens about 3/4 of the time when I try starting it.
I just swapped out the IAC valve and haven't really got a chance to see if that was the culprit. Is there anything else it could be?

Did you check to see if the IAC passage is clogged with carbon deposits?

Should be the IAC..make sure it was installed correctly.

It looked good in the TB.

loose vaccum hose?

Nope. There all good.

Sounds like you need to lean the mixture by opening the throttle. Maybe the PCM is getting the message that the coolant or combusion air is way colder than it really is, and provides too much gas.

I would check the intake air temperature sender and the engine coolant temperature sender to make sure they are working properly.