I have a n/a 1990 300zx M/T with a vg30de the car starts and runs, but it seems that the 1st and 6th cyliner arnt working i unpluged the coils and it had no affect, i was told its either the ingnition coils or the fuel injectors i know its not the coils i assure you. I did a full tune-up but didnt change the pcv plugs (i Will but is it important?). the car drives very sluggish and when i giggle the fuel injector wire-harness the car sputters also it idels at 2k rpm after i have been driving a while...what should i do first? i hope you have the answer to my question im dieng to get it fixed i hate driving a rice burner i will do anything to gfet this problem fixxed!!!

 

Test fuel injectors. I just told someone how to do this not even 3 days ago, so look around for the procedure.

And PCV's will make a difference if they're clogged.

 

if you jiggle a fuel injection wire and it changes something, then there is obviously a problem there.... start with the basics... A car needs 3 things to run properly: air, fuel,and spark. elimate each problem one by one.