I have an 03 G35 sedan. Occasionally (a few times a year) when I attempt to start the car it will start and then stall. Sometimes, if I am paying attention and quick enough I can give it some gas and it will start. There has been a few times when the car won�t start at all. On these rare I put in octane booster and it fires up. However, I am not sure if this is just a coincidence or not. There is usually a real weird smell when it struggles to start. I can only best describe it as an exhaust or emission smell. Also when Im stopped, the idle seems to be a tad bit off, not a really rough idle but slightly off so to speak.

The car has done this since I�ve had it (about 8 years). At first I thought it was just bad gasoline. Would having a shop run an engine diagnostic test detect the problem? My check engine light is not on.

 

You need to clean your throttle body.

 

What dirty said should help. Search YouTube for g35 sea foam. Would recommend resetting ecu, trying a different gas station as well.

Also if you don't already use premium gas, try it for a couple of tanks.

 

If you aren't using premium, you have no business owning this car.

 

Whoa there...lol...I have run nothing but premium from day one. But I will check the throttle body. I hope its that easy of a fix.

 

No, I'm not saying you weren't, I was just making the statement. For all the fuss people make about 3hp from a CAI for instance, it would be foolish to use regular.

Anyhow, if the stalling is worse on warm starts than it is on cold starts, I guarantee that's what it is. Get some TB cleaner, a toothbrush and some paper towels and get that soot out. Spray the hinges of the butterfly really well. Try not to open and close that butterfly too much. Try to hold it with one hand and spray/clean with the other.

 

Thanks for the reply. Well at least I will have something fun to do this weekend. Seems simple enough just worried about having to do an ECU reset. Again thanks for the feedback.

 

Pull off the negative battery cable. Then do the TB. then you no longer have to do an ECU reset.