Try pulling your EFI fuse instead of your battery cable. I found a few times depending on what other grounds you have, the ECU will not reset by pulling the negative cable. Your supposed to be able to pull the fuse for like 10 seconds, but I pull it, go have a smoke and shoot the shiz for 5 or 10 minutes. Once I plug it back in, its always cleared.

Good Luck man, hope you get it figured!!

PS - My other thought was a clogged fuel filter