HELP ME! I was driving back home from vacation using my cruise control. The car automatically breaks when approaching another vehicle, and although there was no one else in front of me, my 2009 g37s started slowing down on its own. I could not accelerate. It felt like my car had accidentally shifted into neutral. I pulled over on the interstate and turned the car off. I was about 30 miles from home, so I turned it back on and got back on the highway. Every couple of miles, the car would hesitate or sputter, all I could do was punch the gas and hope that it stopped. I made it home, but I don't have a regular mechanic and I don't know much about cars, I really don't want to get ripped off taking it to the dealership. Is there something wrong with my transmission?? The car has 100k miles on it but I've never had any problems at all with it before. None of my dash lights or check engine indicators were on. Ideas what it could be?

 

Seems like that sputter is related to engine missing issues instead of cruise control issues. Do you have any warning lamps?
I suggest if you do to get the light scanned to determine any faults without it you are bait and bound to what any mechanics say.

 

Just curious as where your from? As bull mentioned likely not your transmission but engine.
have to maintain the car well? When was the last time to change your spark plugs?

 

I live in Kansas city. I had a buddy come over last night that knows car, we took her out on the highway and drove for awhile but couldn't replicate the sputter I felt, the car drove just fine. That would mean my problem is electrical and not mechanical, right? I called a local mechanic and they told me if I can't get the car to do it again, all they can do is inspect what "may" be wrong, and that I'd be better off driving it until she does it again or it gets worse....

I get regular oil changes and all my fluids are topped off and changed on schedule. It is time for me to get a maintenance check though, we just hit 120k miles this weekend. Like I said, I've never had any problems with my baby before. I should mention that none of my warning lights (check engine, check oil, etc.) were on, and my engine sounds fine.

 

If weather was not a factor meaning rain. It could be a coil pack going bad but it is difficult to tell without a engine light.best thing to do is ask friend for a visual inspection of wires and connectors.till then hope its nothing major .

 

Unfortunately this it what it points to. Not being able to replicate leaves you back to square 1.
You can trust that what ever it is it will probably come back. When it does make sure the car detects the problem by throwing a warning light, without it you along with others are just playing guesses.

 

Well thank you guys for the help I'm taking her in to get the 120k service, Infinit said $1250 but they give me a loaner car so maybe it's worth it. Maybe they will notice something while they are in there.

 

What does the 120k mile service include?

Be careful that they're not charging a fortune for things that you can easily DIY, e.g. wiper blades, engine air filters, cabin air filter, throttle body cleaning, etc.

 

Agree. Online search yield this:

Common services included in the 2010 Infiniti G37 V6-3.7L 120,000 mile maintenance service
Service Name
Air Filter Replacement
Cabin Air Filter Replacement
Change Oil and Filter
Cooling System Flush
Check Brake, Steering and Suspension System
Check All Hoses
Check All Fluids
Check Exhaust System
Check Driveshaft
Check Evaporation Emission System

Which boils down to:
Replacement of air filters and cabin air filters along with an oil and filter change.
The rest are inspections which for the most part are visual.
In parts you'll spend about $150 at most on aftermarket parts possibly $300 if you went the oem route.

It breaks down like this:
$300 parts
$900 in labor ( 2 hours of installation + the other possible 3-4 hours for inspection which in all reality you're paying the tech to inspect the vehicle)
I believe that this service also includes the serpentine belt if I remember correctly, none of these will possibly help with your issue.