wow, I forgot about this thread...

Our solution was the fuel pressure regulator. Even though it tested good, we were out of options, so I said F it an bought one anyway. After we replaced it, which was a piece of cake, the car starts perfect now.

I would say if you have this issue, just replace the fuel pressure regulator and I bet that's the issue.

Thanks guys for all the advice and helping me get to the bottom of this. It was driving me nuts!

 

I don't know if you've tried this or not, I didn't read the entire thread, but mine was doing something very similar and then one night it got REAL bad.

Turned out it was the fuel pressure regulator. 10 minutes and $35 later it starts like new every time.

 

I had the same problem with 2001 ss , fuel pressure was good but changed pressure regulator, fixed the problem was cheap and easy to replace, good luck........

 

Had difficult warm starts for a while now. Had the car in the shop getting some exhaust work and the tech working on the car said it was the AIC. I was going to replace it but did a little research here first and it paid off, replaced the fuel pressure regulator and car is back to starting like new. Thanks again MCF!