Could be an O2 sensor fault. I had a massive crack in one of my intake tubes and car was still running and idling fine. Also run some concentrated fuel system cleaner through it and swap in some K&Ns for a bit of extra kick.
@@gustavedorantejr4372 yeah, when I had my leak, I couldn’t even hear it and it sounded perfectly normal, I just went around tightening every single bolt and I found where it was slightly leaking
I just fix the problem on my g35. I changed the 2 o2sensor and nothing, then i decided to look very carefully in to the engine and I found the little house behind the driver side throttle body was cracked 😳, i replaced and the rpm back to normal again.. guys check for any vacuum leaks.. don't waste your money like me.