Help S13 sr misfire

So I was in the drive-thru and out of nowhere I started getting a misfire. Car started shaking and sounded like a subaru. So I headed home and a few blocks away from my house, it stopped misfiring. Well that’s weird so I drove around for a few hours to see if the problem would come back. Car ran fine. So I’m out driving the next day and out of nowhere it started missing again. Pulled over and started unplugging coils. Found out it’s the #3 cylinder. So I swapped out coils with a known good one and still misfires. Changing spark plugs made no difference. So far I’ve check for vacuum leaks, made sure no connectors were loose or unplugged, swapped coils and plugs. And I have a e5 ecu that doesn’t have the screw so no way to check for codes. S13 blacktop sr20 with bolt ons Isis t25/t28 @9-10lbs Any ideas?