I have a 2006 g35 coupe 5AT,

Mods:
- K&N SRI w/ Injen Nanofiber filter
- Motordyne 5/16 spacer
- Megan Headers
- Invidia Test Pipes
- HKS Rep catback
(Custom X pipe, No Resnator)

When I start my car, it has a farty sound pudder for literally a second, then normal as warming up, once it's completely warm, my RPM goes to 500-550 idling and drops every 30seconds or so to about 300 with a dying motor sound, then back to 550 normal. Just repeats as it idles... no power loss noticed but my car does have a louder and more backfire

I've changed:
-MAF
-camshaft sensors
-crankshaft sensor
-air filter


Need all reasonable suggestions please and thanks!!

Either take it to a local auto parts store or buy an OBDII scanner and download the Torque app to see if you can find a fault code. Sometimes our cars will develop a fault, not set off the SES but still throw a code. Not really sure why but it happens.

Other than that I've got nothing else, sorry.

What's the best OBD2 that'll work great with the torque app? Cheap also

Lots of options out there like this one. https://www.amazon.com/Goliath-Indus...canner+android

However most work well, just make sure whatever you buy is compatible with your device.