you may have a dying fuel pump.. 2cents.
in my twelve year driving/wrenching/racing experience i have never seen a fuel pump "dying" from my experience they just die. i have had the pumps go on me over the years. one in a grand am, one in a 2002 dodge truck, and one in a 98 civic. every single one drove and ran fine when i parked it for the day.......tried starting in the morning, or the afternoon and nothing. fuel pumps were the cause. brett and john feel free to chime in you guys probably see a lot more pumps than i do......just from my experience its a lot more common that the pump just stops working.
if you did just do your timing belt......did brett do it? if so timing marks wouldn't be in question. mine idled like that and fixed itself after the car was warmed up, although it sounded different and idled really high when it was warm. drove fine too. infact it felt like it had more power up top. check all electrical connections, and wires in locations where recent work was being done. i mean even when my timing marks were infact lined up and everything was somewhat running normal. my car still kind of idled like yours. hahaha just a dsm thing.
