My car drives great however, I can't hold a steady 1100 rpm in neutral. When I try to, the rpm jumps between 1050 to 1150 and I hear a lot of popping/backfiring from my exhaust that is synchronized with the rpm jumping around.
I have no idea what the issue could be?

My idle also jumps around 800-875 but there is no backfiring noise.

Higher rpms ( 2500+ ) hold steady.

2004 350z

 

Did you just get it tuned?

If so, it needs more work.

Could also be a dirty MAF sensor, or a bad spark plug, coil, ect

It would help when asking a question like this if you gave some history of the car and what modifications.

 

Tuned a long time ago.

Cleaned MAF a few months ago, coils all new, spark plugs all new.

It has vortech v3, borla exhaust, kinetix plenum