200sx se-r hesitates off idle

[moso]

i have a 95 200sx se-r with the sr20de 5 speed she has 150k and for the most part runs like a champ. i just bought this car in september and my girlfriend has been driving it. here is the problem. when you blip the throttle it stumbles just off idle before picking up rpms and occasionally while idleing it will miss once. and i mean occasionally like once out of three times sitting through a full cycle of a city light. i have checked and/or adjusted and/or replaced the following

MAF - new - excelent groundTPS - new- .052vIACV - cleaned and adjusted - base idle 680rpmsTiming - adjusted - 16btdcfull tune up including NGK plugs and oem wires cap and rotornew fuel filternew air filter (K&N Filtercharger)consult cable used to check for codes - none present - all sensors functioning normallyreplaced all vacuum lines and cleaned metal line under BPT valve.

now i have no idea of what condition the fuel pump or fuel pressure regulator are in and i know i need to change the timing chain which is slated to be done just after xmas. but am i missing something else? any help is appriciated.
Modified by moso at 5:10 PM 11/24/2009

[moso]

bump because i dont like stumbling motors

[nametakennow]

Base idle ought to be more like 750-800. Check the EGR.

[moso]

so i followed your advice and bumped the idle up a bit, now its arround 740-760. i tested the egr valve and it functions fine, doesnt leak any vacuum and opens good and wide. i tested the bpt valve and it failed, so i replaced it with a working one from another se-r. it still misses occasionally but that no longer bothers me because it developed a miss at arround 1900rpm. if i warm the motor up (havent tried this cold) and gently accelerate to 2500rpm there is a noticable miss as i approach 2krpm. as i slowly decelerate when the car hits 1900rpm it drops at least one cyl and simply wont run steady at that speed. it seems fine at any other rpm. also i did this while my consult cable was hooked up, it showed that my TPS voltage was just over 0.6v and seemed very responsive. the other sensors seemed to be functioning fine as well. however after this i did get a cyl 1 misfire code. i am at a complete loss, any help would be appreciated.