Hello everyone. I have a 2007 G35 Sedan which I purchased about a month ago. It has been a pleasure to drive until today. My battery died on me so I went ahead and replaced it. Car starts up like normal but once i start to accelerate, if i go slowly, the car hesitates at about 1200 rpm for about a second and upon that hesitation it has turned off on me a few times today(happened to me 4 times in parking lot where i usually accelerate slowly). if i accelerate quickly or if im idle, it wont turn off. Could this be related to the ECU and "learning" process? after i replaced the battery i had to go to work and drove about 3 miles city and 20 highway. any ideas? Thanks in advance.

 

i also noticed my RPM when i first start car is now lower than it was before. Prior to battery changed when i first turned it on it would be at about 1400 RPM, now its at about 700-800

 

Once the car starts, the alternator provides the juice. Have it checked. And check the belt tension. I have a radar detector that outputs voltage when I suspect electrical issues. Alternatively, you can hook up a voltmeter but see what voltage is being put out.

 

thanks for the response. just got home and on the expressway it was a breeze; car drove awesome. once i got into my gate community where theres a lot of speed bumps the car turned off on me once as i accelerated slowly. i'll get the alternator checked but i was thinking it was more of a "relearning" issue.

 

Check your o2 sensor also. My car did something similar. I popped the hood and realized the o2 sensor popped out. So the car thought it was suffocating and turned off.

Hope you fix the problem. Enjoy your G

 

Car should never stall out or turn off while driving!!! Definitely NOT a relearning issue! It is a serious problem and potentially dangerous.

Also, by "turns off" are you saying the electrical is out or the engine stalls out. Big difference.

 

The engine stalls I put the car in parking and when I try to start it, it starts up right away. The problem is limited to very slow acceleration. like if youre in a shopping center for example and have to drive rly slow if i accelerate quick no issues.

 

After reading a number of posts im beginning to think it may be throttle body related. lets see

 

***UPDATE***

So i went to the dealership and they reset the ecu back to factory. (2 codes had come up; B2109 and B210A. )

Dealer said ecu reset should do the trick. I drove off on my way home with cautious optimism. I knew the real test would come when i got off the highway. So after 15 mins on the highway i get back into city traffic. I accelerate slowly, and hesitation is back. One thing i did notice is that its not stalling on me anymore but with that hesitation at 1k RPM im still with that fear in mind. I drive back to the dealership and had them sit in it as i showed em the hesitation. They acknowledged it shouldnt be doing that. After further testing, they told me its the Valve Body. Part costs $1601 plus about $500 in labor. My car is out of warranty(2007 G35 sedan, 87k miles). Is this something worth fixing? The guy told me i should be ok for a while. what would you do? Thanks

 

have you noticed that the RPM would go up and down? esp when idling? and does the car makes weak engine notes???

well, it sounds like a throttle body clean up time. Seriously, it's very easy to do.. and make sure to do the ECU reset to relearn the throttle positions. (I'd just pull the battery power and leave it off over night)

This should clear up the stalling issues, hence I had the similar issues. I'd recommend doing throttle body cleaning process every 10,000 or a year. which ever one comes first. also get a new orange gasket (the throttle body gasket) to replace it, if they look worn out.

 

Woostar,

as a matter of fact when idling i do see the rpm's go up and down from time to time. also, sometimes i turn car on and RPMs stay at like 2K rpm other times like 1K. I really think the dealer might be bs'ing me. when i shift moderately or quickly i get no hesitation and the tranny feels way smooth. the only issue is when the car is warm and i have to accelerate slowly that i would feel the hesitation and sometimes it would stall. i tried accelerating the car slowly while in car in parking as well as in neutral and i would still feel the slight hesitation. Thanks for the reply. i really hope a TB cleanse does the trick.

 

Yeah buddy, dealership is stealership for a reason... Honestly, it doesn't hurt to do throttle body cleaning. You'll only benefit from it. Just dont forget to reset your ecu after doing so.

Also, I'd clean the MAF sensor as well. Keep us posted and goodluck

 

so it looks like the problem is a little more serious. car consumes oil like crazy and the white smoke that comes out of the exhaust from time to time is very concerning. finally found an honest and trustworthy mechanic and he told me that the solution would be to have the engine rebuilt, but his suggestion would be to get rid of the car because even with a rebuilt engine there are a lot of unknowns. next time i get an infiniti it will def be CPO. for now a 2011 accord with very low mileage and CPO will do.

 

Sorry to hear. I guess that's another reason I only buy new cars but usually keep them 10 years or more.

 

It isn't a bad idea to buy used cars either. My car was bought used at 21k miles and 2 years old and it now has over 79k miles and still runs like new. My car was over $14k off MSRP, and it had every package available except the sport package. Every mechanic I brought it to for maintenance says this engine was properly maintained and everything is clean looking. You don't have to buy CPO, but buy it with at least a full year of bumper to bumper warranty left on its original warranty to protect yourself. CPO is just another reason for them to charge you thousands more.

It all depends on the previous owner and the service records. I don't know how the OP acquired his car, but perhaps it wasn't serviced correctly by the previous owner. Also, looking at his previous posts, the OP did say he got the car for a "really good price" at the dealer. I suppose you do get what you pay for. The dealer might have already known these issues and sold the car without any type of warranty and the OP took a gamble. Buying a CPO car, the OP would probably pay the same amount extra and would have covered the cost of the Valve Body replacement anyways.