R34 Non Turbo Ignition Problem/engine Splutter Need Help Please

[IMPORTS ONLY]

So ive got a 98 Non turbo R34, i had one coil pack go a few months back and replaced it, since replacing it i noticed when i started my car occasionally it would die unless i keep some revs on it for the first few seconds and would usually stay jumpy around 700 instead of steady on 1k revs . i thought this could be the spark plugs or other coil packs because im just under 100,000 k's so i went and got a set of 6 coil packs that were off a low k's 34 in perfect working order and some new nismo spark plugs 0.8 heat range 7. fitted them all, noticed a vacuum purge in one of the rubber grommet seals on my rocker cover fixed that and put everything back together but problem still there. i just replaced the O2 sensor a couple months back so last thing i could think of was the fuel pump, got a new one fitted and same problem and now i also have an occasional put put sound that comes through the exhaust. sounds like the timing of the engine is off

and now im out of ideas on how to get it running mint again

i have a video of the car struggling to start

http://www.youtube.com/watch?v=pvNUk18iGX4&feature=c4-overview&list=UULMTc8BU-SPQo_YbXqXHwpg

and a video of the put put sound, its kind of hard to notice it through the recording

http://www.youtube.com/watch?v=1c31tleK8GM

has anyone gone thought this or have any ideas on what else it could be