So after I hooked up my Haltech, I got a strange misfire for 3-4 minutes after I restarted it after fueling up. Didn't matter if there was 1/4 tank left or it was completely empty. Pulling the gas cap still didn't make it misfire, so it had be to fueling up.
I finally solved this problem this weekend. I installed my secondary intake manifold with 440's and a parallel fuel line mod, removed the purge control solenoid and all the extras, and capped all the extra lines.
Just fueled up a few minutes ago and lookie... no problem! Damn purge control solenoid was causing a misfire, I'm guessing from auto matically releasing into the manifold after fueling up and starting. Doh!
Well, this is just an FYI in case anyone else has the same strange problem. I'm probably the only freak that went through and reconnected all the grounds that had been connected with the stock ECU, but you never know.