I have a petite racing midpipe and a HKS hi power axle back. I’ve noticed it always backfires when it’s cold out and I let off throttle. I have a boost gauge and I’m not boost creeping at all. Any idea why it does this?

 

Cars run richer when cold to help with warm up. More fuel means more potential for back fires. Though, if you have the above exhaust you probably aren't on the stock ECM, so maybe check your fuel maps?

 

I’ve had the midpipe in for a short time, just waiting on the power fc my buddy gave me to get the base map flashed back on. That’s why I’m wondering because if anything I should be running somewhat lean