Hi all,

From the DC area, past two winter seasons my 2004 G35 sedan has had starting problems after sitting for a while. typically in the mornings when I try to start my car for the drive to work and evenings when I try to start my car for the drive back home.

The symptoms start in fall around the time mid October around the time of the first 40 degree day and stops in spring around mid April when the days start to get warm again around the time we hit out first 65 degree day

winter starting symptoms:
turn ignition key, engine turns over, fails to start
step lightly on gas, turn ignition key, engine starts, quickly step off gas, engine dies.
step lightly on gas, turn ignition key, engine starts, continue to lightly press gas pedal for 10-15 seconds keeping engine between 1000 - 2000 RPMs, remove foot from gas pedal, car runs fine, car will start fine until it sits for another 6-8 hours, i.e. when I'm running errands, no issues with starting.

I was thinking that it would be a seasonal fuel mixture, but then more than just me would be having problems like this. or maybe a fuel filter, but I suppose I'd have other starting issues. Any ideas?

ps. battery was recently replaced, and no engine codes are being thrown.

 

Are you putting premium gas (91octane) in the g or is it the lower octane gas? Also how much ethenol is in the gas you're using? I know there are a lot of states putting ethenol in their gas which I've noticed leads to less gas mileage but may have some performance hindering attributes to it as well. Since the vq35 engine isn't expressly set up for ethenol.
Just some ideas. Going through my head.

 

Shouldn't make any difference in how it starts using E10 fuel, and/or lower octane.

 

Sounds similar to the issue alot of people have reported, there are quite a few threads abou this. I jus picked up an 04 in November, mine would start when cold, the RPM's would drop and it would stall most of the time unless giving it gs. Had the TB cleaned - nothing, new MAF and haven't had an isseu starting since. I'm in the midwest and we have a couple COLD nights, still starts fine. I neer saw a code, jsut from readin here decided it was time tocheck the TB and MAF, or as some called it the air idle intake valve.