I have a 2011 G37 that has been stuttering when idling and accelerating and backfiring when idling. It has gotten progressively worse over the past two days. I noticed it after getting a full tank of gas, so could be bad fuel but I put fuel cleaner in and it didn’t seem to make a difference. Also recently changed the driver side VTC solenoid so not sure if that could be related. Going to take to shop asap if issue doesn’t resolve but wondering if anyone has any ideas on what it could be.