Strange whooshing noise.

[PW39]

A couple of weeks ago while driving my 2007 auto 1800 Avensis I had to accelerate quite hard when exiting from a side road into a busy main road. Immediately after this hard acceleration there was a very disturbing loud whooshing roaring noise, not a continuous noise but a slow pulsation. It felt like a build-up of gasses and something had blown.
I had to continue on through a town and the noise was now less but steady, I stopped and inspected the car and everything seemed okay.
I continued my 37 mile journey home, still a noise but performance seemed to be unaffected.
After a few days I still felt there was still a slight noise problem, I might be imagining this though.
I have just had the exhaust system checked and it’s fine.
Has anybody else had this experience?

[Byzii]

Hey,

It's quite hard to understand what noise you're talking about, things like whooshing and roaring simply don't mix in my head so if you could find a similar noise on YouTube or even record it that would aid in faster diagnosis.