i don't know if anyone else has had this happen to them but when i am driving my engine sounds normal until about 2500 RPM then it gets deep until about 3000 then it goes back to normal. i was just wondering if anyone thinks that it is a problem or if it is something normal. thanks everyone for reading this

 

Uh.. it's probably normal unless it's really loud. The "deep" sound should go away and become higher pitched/louder.