Hello everybody, I have a 2011 G37x 7AT with 146k on the dash. A few months ago I started to experience random, intermittent misfires only during cold starts. No SES on dash or flashing SES at WOT. Replaced a few things and quit throwing the pending code. Car now hesitates from stops and slight bucking/stuttering between 1-2k, lead to believe the issue is still present just not bad enough to trigger the pending code. Also getting P0171 occasionally. (MPG has also dropped to 9-10 city depending on traffic) Any help or feedback would be appreciated. Thanks!

Only codes in past few months are P0300 which it no longer throws, P0171 occasionally, and constant catalyst codes for tp’s

Recent maintenance/check overs

• Spark plugs & coil packs
• New plenum gasket
• New valve cover gaskets and spark tube seals
• Fuel pump and injectors
• Tested oil pressure which checked out fine
• Bank 1 maf occasionally jumps up past 15 at idle. occasionally goes as high as 18
• Idle rpm is at 500 in drive, AC brings it up to factory spec of 650

Mod list

• 2.5 inch z1 intakes
• Pump and injectors for e85
• Full exhaust with test pipes
• Tune on 93/E85