Hey everyone, I'm having a little issue with my dad's Camaro I swapped a 5.3 /4l60 combo in. So, it started to do a backfire through the exhaust on some mild to moderate acceleration. I called my tuner who is somewhat local to me, had my dad drive it down there where they went for a drive retuned it and fixed its issues he said. My dad drove it home and was going by my house when the problems came back, I drove it and it felt like he didn't do a thing to retune it however my dad said it was totally fixed when he was there .. only when he came back this way and got off the freeway it started to act up .. When I drove it, it backfires and breaks up but more throttle and over 4k I'd say it clears up and is fine. even on a cold start, I drove it and it starts to break up at about 30 to 50% throttle. My question is what could this be and what should I be looking for and logging in the Vcm scan? Before you guys get on me about posting the tune Yes, I can post the tune, but I need to get down to his house with my laptop 'I was more curious to see if this is an off the top of your heads issue like a bad 02s etc. . I just don't know on this one ..
73 Camaro
60e
5.3 lm7 cam only
p59 ecu
Thank you for the insight in advance