Popping sound when revving engine on '04

[showme]

Still working on my adult daughters Quest to get it ready to sell. Just installed a new fuel pump after the old one stalled after adding seafoam and octane booster to the gas, which has been in there since last summer. I believe this clogged the filter in the pump, so I put in a new one. Now, it's starting and idling fine, but when I rev it slightly, There's a loud pop that comes from somewhere forward of the drivers seat, which makes me think it's an exhaust leak, bad gasket or worse, a clogged catalytic converter. And since these vans have 3 cat converters, I wanted to ask the folks who know these vehicles if you've ever had this happen, and if so, what was the solution? I'm really tempted to just put it up for sale as is and let the prospective buyers know that it needs attention. I'm definitely not buying and installing new cat cvtrs for a vehicle that we're selling. Gaskets, maybe, but more likely just letting lookers know that there are some issues to be fixed. But I'd at least like to be able to give them an idea of what those issues are. Thanks for any help on this. Lee

[VStar650CL]

The best way to verify if it's an exhaust leak is to have an assistant block the tailpipe with a shop rag while you poke around. Increasing the backpressure will make even a pinhole leak loud and palpable.

[showme]

Thanks again, Vstar? I'm beginning to think if you weren't on this forum, I'd never get any replies. But, thanks to you (most of the time), I'm getting this thing accomplished. Lee