Stuttering/ surges

[aleda21]

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?

Thanks for any help!

[Ziggy1621]

Moving to tech forum.

Welcome to Nico! when you say you fixed those cylinders, how did you fix them. If the injectors are starting to go out, they usually go one at a time until you replace them all. So I would suggest saving up and getting those replaced.

Are you getting codes? http://www.nicoclub.com/archives/nissan ... ostic.html

Have you moved around coil packs to see if the dead cylinder moves with it?
Do you have a new or old PTU? If it is new, clean the connections and I always suggest soldering in the pigtail rather than having the extra connections.

[t.mcginley.jr]

Definitely check for codes first.

You probably have a bad coolant temp sensor or something. Btw, you would have been better off just saving up for a new style injector conversion kit + a set of reman'd (cleaned) injectors. The old style are all going to fail eventually because the ethanol in today's gas will corrode them from the inside.

conversion kit: http://www.z1motorsports.com/product_in ... ts_id=3348 $129

new fuel rail seals: http://www.z1motorsports.com/product_in ... ts_id=5220 $10

reman'd injectors (just search ebay for 300zx injectors if this link doesn't work): http://www.ebay.com/itm/1-YEAR-WARRANTY ... fa&vxp=mtr $100

[t.mcginley.jr]

You can also pick up a new-style PTU off of ebay for cheap, like $20:

http://www.ebay.com/itm/93-Nissan-Maxim ... 3a&vxp=mtr