I've owned a 2004 G35 since new in 03. I’ve done all the maint. myself, except tranny maint., so that I know it was done as required. My question is this. Our car has 90k on it now and has started to die when first started when the engine is warm. Its acting like the idle is too slow. When you restart and give a bit of gas its fine from then until the next warm engine start. Has anyone had this problem? Also, we're in the midwest and our fuel now is 10% ethanol. Could that be part of the problem? Thanks for the help in advance.

 

I have not seen a problem like this before. It could be a vacuum leak or a dirty mass airflow sensor. I would clean the MAS first and see if that helps.

Worst case you can have the dealer up your idle a little to help.


I'm going to move this to the engine section where it will get more people looking at it.

 

Welcome to the forum, and good job that you've kept up with your maintenance needs. The symptoms you've described indicate that it could be a dirty throttle body as I ran into a similar situation with my previous car. The throttle body just needed to be cleaned up which you can certainly do on your own (part 1 video: , part 2 video: ) but I took it to a dealer at that time (wasn't particularly car-saavy back then). One hour later, the car started fine and drove like normal.

Let us know how this works out for you.

 

Have you changed your plugs yet?

 

+1 on throttle body

Several people had this problem, including myself. It should be a simple fix unless your throttle body sensor is sensitive, then you have to do a reset on that after you've clean it.

here's the thread...
https://g35driver.com/forums/g35-coupe-v35-2003-07/170218-help-engine-dies-right-after-starup.html

and...
https://g35driver.com/forums/engine-drivetrain-forced-induction/182685-car-shutting-off-start-up.html