Z31 non-turbo running rough

theres lots of things it could be, check if you're getting spark and fuel to all cylinders, check for vacuum leaks, make sure your MAF works right, the list goes on...

A mechanic friend says the hoses that connect to the throttle are leaking air. I am having a hell of a time looking for them in auto parts stores. I will probably end up taking them off in a junk yard! I already replaced the mass air sensor.

i dont know if they are form air lines on the z31, but on my z32 its just regular 3mm vacuum line

I had the same problem. Check for lose O2 sensor!!!