Alright, I'm a total noob, so please go easy on me, but I've used this site before to help me do routine maintenance on my STi, so I'm hoping someone might be able to help me out.
My 2005 STi is completely stock and only has about 65k miles on it, it runs great, I keep it well maintained, and I've never had any problems with it. This morning it wouldn't start. The engine would crank, but it wouldn't turn over, so I know it's not the battery. I also doubt it's having problems getting spark, since I just did a tune up on it in June and replaced all the spark plugs. After a bit of google, it seems I might have an issue with the fuel line? But there are so many components to the fuel system, so I was hoping some one might be able to walk me through trouble shooting what might be going wrong. I've already checked all the fuses (apparently #11 is associated with the fuel pump), but none have blown. From a visual inspection of the supply and return lines in the engine, there doesn't seem to be any physical connection issues. Some people have mentioned having problems with the fuel pump control unit located in the trunk. I really have no idea where to start or what to look for. Can someone tell me what I should check, in what order, and how to do so? I have basic tools, and I'll rent or buy tools and parts as necessary, but I can't afford to take it to a shop.
Other info that may or may not be relevant:
-It's pretty cold today, but at 27 degrees F, I don't think that would be cold enough to cause any issues.
-The car was in a flood back in August. The water didn't come as high as the dash, but I had to take it to a Subaru dealer to get it running again. Though $2,000 later, it seemed to be back to its old form, running as good as new, and has been running great since then. But I've read that cars that are flooded can have electronic issues crop up long after the initial flood, so it might be possible that something is funky with the computer.
Thanks in advance for any guidance.