Here's some of the background info:
Car starts everytime.
Sometimes it starts absolutely instantly after cranking.
Sometimes I need to crank it about 5 seconds until the oil pressure gets up a bit.
Fuel pump always primes.

I think the problem started right after my Speed Density swap. The car runs absolutely flawlessly. What should I check/troubleshoot?

 

Are you still using the CSI, or was that eliminated with the S/D swap (doesn't have to be)?

 

Does it have to do with how long the car sits? I had an issue with mine and it turned out I had VERY leaky fuel injectors. Swapped over to my 24#'s with no leaks, and my car started right up instantly every time.

 

The CSI is sort of very loose. I was looking over plugs and saw that the plug sort of rattled around- I'm not sure if its the plug or the injector itself. I didn't knowingly bypass it, I really have no idea- I just followed the wiring diagram on the tech article. I don't think it is consistant with the amount of time its been sitting.

 

If the car sits all night it usually starts instantly. But when I run errands or if it sits for only a few hours it won't always fire up instantly. I'm not sure if its a heat issue or a dying pump or something else.

 

That sounds like a typical fuel loading problem. Duron was alluding to that. Leaking injectors are a prime suspect, but a leaking FPR can do the same thing. You'll have to test and monitor fuel pressure after shutdown to help determine the source.

 

That's EXACTLY what my car used to do when I had my stock 19#'s. It was clear how bad they were leaking the one time I ripped my TPI apart and heard the hissing sound. My 24# injectors don't leak at all and my car started right up when it was running. Hopefully I can get lucky and it will start right up when I drop the new 355 in

Reason the car works in the morning is because the car has sat long enough to let all the fuel evaporate. Leaky fuel injectors hurt emissions (even though I passed once with flying colors after a few failures), and hurt gas mileage. Couldn't compare as to how much though because my engine only ran for a few days with the 24#'s before I spun a rod bearing.

 

Would my CSI have anything to do with it? Any ideas on prices? Stock replacements or aftermarket? I've never looked into injectors and know nothing about them. The odd things is that my car was fine before my SD swap so I think I bumped something (the 9th injector most likely).

 

You shouldn't have the 9th injector plugged in anymore if you swapped to S-D...

 

I also had the same symptoms, and it was leaky injectors for me