I'm running a Ford 5.0L with a microsquirt computer in a Miata. Basically a 1991 Mustang with Miata skin. The engine has been over bored 0.04" and has a Crane cam, which one I'm not sure. I purchased the motor from some else and the info is not available. It has Trickflow heads and Intake with a 75mm TB, 24 psi injectors, 14point7 wideband O2 sensor. When I first started the motor it had open headers and no O2 sensor and it ran fine. I didn't capture any data or make any changes to the tune that came in the computer. I had a custom duel exhaust installed which has high flow through catalytic converters and mufflers. After the exhaust installation I can't get it to idle without surging. I have gone through the timing setup, TPS and sensor cals and adjusted the idle set screw that will allow the engine, although surging, to warm up and the surging will stop and idle at around 1100 RPMs. I've watched all of the A91what videos and I tried to collect data for the IAC test but when I change the IAC above 30% it starts surging and I can't collect any good data. I tested the IAC and it appears to work fine. I'm attaching my setup and data I collected while it was warming up. Midway through the warmup I changed the timing to fixed at 20 deg. Please Help.