1987 ignition timing problems

I am having very bad ignition timing issues on my 87 z31 with an na2t swap. The car is running extremely rough if it even starts. And if I check the ignition timing and set it to 20 then rev it, the ignition timing will retard. Then after sitting for a little I will check it again at idle and now it's at 10. It will jump from anywhere between 0 and 50. It's really bad. I've already tried the distributor out of my 86 and that didn't fix the issue. Any ideas on what could be causing this? Bad ground somewhere maybe?