It's a long shot, but...

[Neural]

apparently 90 to 99F in the garage for a couple weeks straight was not that good on my 4030.

Everything else paintwise seems fine, but the 4030 is a bit like Molasses. Maybe slower. It's not completely dry, but it doesn't exactly want to move either.

Can I use 4012 to thin it up, or is it dead?

 

[Leakyvalve]

Take a look a this thread. I'm updating it again in about 5 min.
http://www.airbrushforum.org/threads/interesting-discovery-4030.20271/page-4#post-318251

 

[J000seph]

Sounds like it is already cured.

 

[Mr.Micron]

While I paint in my garage at those temps I store my paint when not in use in the house where the A/C keeps it a cool 69F
Any paint with an acetone base or urethane will do that at those temps.