I have problem starting the car every time when it's still warm i.e. restarting after filling up gas or restart after parking for less then 10 minutes. the engine would crank up but the rpm drops rapidly to 0rpm and the engine stalled.

The car didn't have this problem until my battery died and i changed it a couple months ago. i already did the ECU pedal pump reset and unhook the negative terminal of the battery over night. but the problem is still there. i don't have a problem starting the car when it's cold (going to work in the morning) or if the car has been park for an hr or more.
this is an 04 non sport sedan with 0 mod. any help would greatly appreciated. thanks!

 

Do a search on cleaning the throttle body. There are DIY vids posted on You Tube as well, just do a search for "G35 throttle body." Seems like this has been a solution for most people with this issue.

 

that or clean the maf sensor

 

I just had to replace my battery yesterday and my car did the same exact thing! I bought some throttle body cleaner and MAF sensor cleaner, took the whole thing apart and cleaned everything. Just finished a couple of hours ago and my car runs alot better now with no problem during start up.

Make sure you also do this after cleaning the throttle body: http://motordyneengineering.com/manual.pdf

And here is a thread containing more useful info: https://g35driver.com/forums/g35-cou...er-starup.html

 

I bought a can of throttle body cleaner and worked on cleaning the throttle body over the weekend . i didn't disconnect the battery and clean it without removing the throttle body unit. Of course, i didn't get it as clean as i could get if i had remove it to clean both front\back of the plate. my car has 65k miles on it but it wasn't as dirty as i thought it would be. since i had everything opened up already, i changed the air filter as well. i drove the car to warm it up to operation temp and did the air\throttle learning steps. This morning, i tested out and the stalling on warm has gone away (knock on wood). i'll keep checking again but it's a good sign so far. Thank you all for your helps in replying to my post.

Even though cleaning the throttle body seems to solve the "warm" stalling problem, like other posters said, how can the throttle body be dirty and works ok (no warm stall) until you change the battery? i guess i'll know some day the root cause of it. thanks again.

 

I just had the same problems with a warm stall immediately after changing my battery.

I didn't drive my car for a couple of weeks following my shoulder surgery so when I finally went to start the car for the first time it was dead. Had the battery tested and it proved to be bad so I grabbed a new one and installed it.

I immediately realized that something wasn't right with the car. Started great and idled fine when cold but it stalled (or almost stalled) during start up when car was at normal running temp. No CEL lights on either. Just like all the other posts that I have read regarding this problem, the car idled and ran perfectly before the battery replacement.

Long story short, I just purchased some CRC Throttle Body and MAP sensor cleaner and did the job. I took the throttle body off to clean it and it was really dirty. Once I reassembled and did all the ECU resets, throttle position learning...etc procedures, the car ran better than ever. Problem fixed.

My thoughts are that when the throttle body and/or MAP sensor was slowly getting dirty over time, the ECU was making corrections and saving those settings. Once the battery died and reset the ECU settings, the MAP and/or throttle body must be running so far out of spec. that the ECU could no longer learn and make appropriate adjustments in order to make the car run as it did before. This is just my guess anyway.