ZDriver.com - surging/ stuttering help!!

before i get flamed for not using the "search function" I have...
So back story, i just bought a 300zx 1992 na with 251k miles, i got a good deal $500 minty interior and exterior has a slight faded paint. But it was misfiring checked the injectors narrowed it down to cylinder 4/6. I fixed cylinder 4 and drove it around for a week then cylinder 2 went. Fixed that then cylinder 3 went. When i fixed cylinder 3 i noticed the cap on the bottom of the injector (old style) was broken halfway off. So i replaced it with a new injector and injector clip. on idle it seemed fine i go to take it for a test drive and it has a weird vibration at around 1500-2k rpm then from there under acceleration it begin's to loose power and surge then after about 30 minutes of driving it doesnt surge anymore really but just has a loose of power. any suggestions what i might be? cylinder 6 is getting fixed this pay check but i've driven it with 5/6 for about 3 weeks and as long as i dont use ac it seemed fine. Also it wont crank now first time i have to crank it 3-4 times before it will actually start

my thought since its intermittent maybe a soft fail ptu? or maybe fuel pump is going?