Need help to fix my nissan

that is strange almost seems like it isnt getting enough fuel?

i got the 4cyl in mine the z24 motor and i love these little engines we rotaited the dist and my god this thing screems lol it runs about 80 in 3rd gear.

never had the 6cy how do they run?

well there is a lil box underneath ur pasenger seat it has a idle control nob on it that u can adjust check that also....

I have an Idea....Sell it!! .
To answer all of your questions the #4 cyl has Zero compression.

are u sure they gave u the right fule pump,that happend to me and my truck did kinda the same thing the fule pump they gave me was to small but just big E nuf to start the truck and  let it idle but when u hit the gas it would hit 2k then drop out,so may be.......

had lots of custom in my life and iv had that happen to me two time on trucks and on both truck i switch out the mass air flow sensor that sets on the side of the t-body and if you look down the t0body there a hole on the left side by the rime of the t-body there a live red wire that sends how much air is getting to the motor and if it gets wet or dirty your truck runs like shit i spent over 1500 buck at nissan to learn that info i how i can save some one some money good luck