So I've been trying to track down an idle midfire for months (if not years?) now.

[Keyan]

I want to get tuned by Pampena but I want this fixed first.

It misfires at idle (just a slight pop in the exhaust). It never really concerned me when I was on the stock ecu, but ever since I put in chrome (obd2) it throws a p0300 all the time. If I reset it, it comes back in 2 drive cycles. It doesn't seem to misfire while driving (or not to my knowledge).

List of things I have changed:
New coils
New PTU
New wires
New plugs
Rebuilt engine (wiseco pistons, lapped valves)
93 ecu -> chrome ecu (misfired on both)
vehicle has a DLI, runs the same with or without it connected.
relay for the coils to get b+ when key on
New injectors
No vacuum leaks
New crank sensor (broke the old one rebuilding the motor)
valve timing is on.

The vehicle has a maft and a 3.5" maf in blow-though just before a 90* at the throttle body. To my knowledge, my car had the misfire when it was also on the maft+safc combo, and I do remember ray had to pull out like 12% on the safc with stock injectors to get it to not run lean. I am thinking maybe the maft or maf is bad.

Is there something I am missing?