Okay, I need a little help on where to start on diagnosing a backfire on an LS1. I recently did a cam, spark plugs, springs, and pushrods on a 2002 LS1. Everything ran fine after the tune for a couple months.
But now, only at idle, and randomly on the passenger side I hear a huge backfire. There aren't any codes or anything on. I don't know where to begin looking though. Has this happened to anyone?

 

Huge backfire or loud popping, not a vacumn leak by any chance. You running cat converters, if yes, is that side part blocked. just throwing suggestions... better to get it looked at, might be a fuelling issue.

 

Check your plug wires. Mine started backfiring and I ended up having 3 wires on the passenger side not fully connected to the coil packs.

 

It's a very very loud popping noise. I have not checked for any vacuum leaks. I did delete the AIR system when I installed the cam. I am not running cats anymore, and my headers have block off plates. I'll start with checking for vacuum leaks and plug wires. I hope it's something simple. It'll do it at almost every stoplight. Someone said flames do come out of the exhaust. So I'm thinking it's a backfire, correct?