Heres a topic simular to my problem.

https://www.audiforums.com/m_315526/mpage_2/key_/tm.htm

I'm kinda confused about it. Since people said they started hearing cracking noises after they put in an aftermarket DIY airbox. Thats my case, after i took the stock airbox out i started to hear these cracking noises, so then i took out the aftermarket airbox and put the stock one back in, its still the same problem, so i have no idea what to do. i read throughout the topic and i have no idea which one is the solution.
-dv.
-re-flash ecu.
-injectors.
-spark plugs.
-n75.

i really don't know? i'm currently boosting 3psi which is irregular. whats the solution to my problem? anyone that can help i'd really apprecaite it. thanks.