I installed a set of headers a couple of weeks ago, would a loose fitting at the flange cause backfire?

 

Loose fitting at the heads to the headers? Or at the flange where exhaust pipe meets the headers?

 

I found y it was backfiring, bad maf sensor they sold me off of craigslist also I found my distributor cap was arcing. There was a harness too close to the cap and it was arcing to the upper intake i corrected that. I disconnected the maf and I got a engine light but it hauls ***! LOL