2004 5AT Coupe
79,000 miles
No mods
Lately in the cold weather when I attempt to start my car in the morning the car starts up then the rpm's drop and it either stalls out or takes a second to properly idle. It has been doing this every morning for a couple of weeks now. I have not had an opportunity to look under the hood but there is no CEL and the cars seems to work properly otherwise. Does anyone have any thoughts? Is there any other info I might need to provide that I did not list out?

Thanks,
Jason

 

Cleaning throttle body fixed this for me, had the exact same problem.

 

its probabaly your MAF sensor dirty or going out. Sensor is locate in the intake system between the box and the g/z tube.

 

I would do a general intake cleaning kit (3M has a pretty nice kit that does your intake runners via some solution you spray into your car throttle body while it idles, has a specific throttle cleaner spray, and includes a bottle of fuel injector cleaner you pour in your tank), and clean your MAF sensor (there are sprays that you just spray your MAF sensor with and then let it try off and it's clean).

Try this, if this does not solve your problem, then I would try resetting the ECU and properly relearn throttle body position and idle along with that.

 

Maybe I'm just skeptical but that doesn't sound like it would be very effective. Plus, there's no way of knowing how much build up is on the TB without actually inspecting it. And if your supposed to spray directly on to the TB with the engine running, the car will barely stay running without the MAF and vacuum line connected and in place.

 

The instructions have you slide the tubing so it sits about an inch in front of your throttle body. The rest of your intake should stay in place (so your MAF and vacuum line are still in place and functioning).

The idea of having the spray so close to the TB is to ensure all of the spray gets sucked into the intake (and so it doesn't gum up the the MAF sensor).

The spray lasts for quite a while (like 5-10 minutes) so I'm pretty sure it coats everything pretty well.

 

definitely try cleaning throttle body and maf sensor...if you have an aftermarket intake system i find that when dirty they usually dont perform well at all in cold weather climates, and that goes for any car....so potentially clean/replace air filter, clean your throttle body, and try cleaning your maf sensor!

 

Mine was doing something similar when I was actually driving. I cleaned my throttle body, Mass Air Flow Sensor and replaced my battery! Fixed the problem so far, and I attribute the stalling to the low voltage I tested across the battery.

 

+1 on the battery. I changed my battery recently and had to complete the re-learn procedure.

 

Like they said, TB clean, MAF clean, ECU reset, Idle air relearn. thank us later!

 

+1

not a big deal, so just get it done and your G will run smooth again!

 

Thanks to everyone for the info! Two questions:
I seached the DIY and did not see anything, but isn't there a special procedure for cleaning the TB. My old car had a simple cable and the G35 is a drive by wire, anything important I need to know?

Any recomendations on a specific brand of MAF cleaner?
Thanks again!