BOV? umm honestly it feels like it is under me/behind...If any of you have ATVs, and you get on it and shift under stress, sometimes it will suck in air(or water in my 4wheelers case) and thats really what it feels like....And it doesn't happen if im not WOT either

 

Blow off valve...was a joke. So it's just sound (no thumping) and it sounds like it's under you? Hmmm...did it do that before your custom y-pipe? What about before you CAI? Which muffler do you have? Yea I know these questions suck..

 

i too have a y pipe....

 

umm well i got the ypipe and duals the day i bought the truck so im not sure and I have a K&N full CAI...it could be like a thump but I would describe it more like an exhaust burp

 

Me toooooo...stocker though not custom

 

i get this in my 4.7 only after flowmaster 40 install if i recall but had exhaust done with in mth of ownership.....and usually midhigh to wot.....oddd thing i just fig it was back pressure its not a tranny issue or anythong its purly exhaust....

 

Mine does the same thing. It started doing that when i put on my catback and removed the resonators. it's just the rpms dropping very fast in comparison with the shift.
I assure you, there is nothing wrong there. I have 5kmi on my truck. Nothing is wrong.

 

That's a hemi fart.