Hi All,

I've had a 2003 G35 coupe AT for the past four years. The car had full bolt-ons (no headers) for engine and suspension. I recently put the car back to stock and parted out my aftermarket parts. I gave the car to my sister to take to school this upcoming semester.

My problem is - after successfully starting the car, the car will sporadically shut off or dip really low in RPMs and almost shut off. If the car doesn't shut off, RPMs will always idle healthily around 675-750. To attempt to fix the issues, I cleaned and re-oiled the K&N air filter, cleaned the MAF, and disconnected the battery overnight. After performing the above, the random problems continued. Does anybody have any suggestions?? The only thing I could think of that I did not do was perform the TB re-learn process (I don't think that would matter as I didn't disconnect the TB).

I had a JWT intake, MD 5/16 plenum spacer, COBB AccessPort tune, test pipes, and Megan single exhaust on the car. All has been taken off (tune was uninstalled from car, stock ecu reset) except for the plenum spacer. Could that really be my issue?? I know a lot of guys run the plenum spacer on a complete stock car. Could my spark plugs be an issue due having a previous richer A/F tune with the aforementioned modifications? I have stock equivalent NGK iridium spark plugs

Please let me know what ya'll think. I really appreciate it as my sister is going 14 hours away to school in Alabama and I want the car to be 100% reliable for her. Thanks!

 

Does it happen on cold or warm starts?

 

It happens on warm starts, never happens on cold starts.

 

Alright. Try cleaning the MAF sensor, and the TB as well.
https://my350z.com/forum/showthread....6#post10182436

 

Clean MAF sensor again. make sure you actually take it out of there and spray it on the sensor.

This was happening to me after cleaning my JWT I added to much oil and it would randomly shut off at stops. Removed MAF cleansed let air dry placed back in. Reset ECU and she has not given me that problem again.

 

that is why i dont like oiled filters,

 

Thanks for the tip. I did disconnect the MAF and take it out of the housing to clean it. I will clean it again nonetheless. Also I will clean the TB and perform the re-learn process.

Does anyone think it could be my stock car with only the MD 5/16 plenum spacer? Any other ideas? The car only shuts off/threatens to shut off on warm starts, but drives like new once started successfully.