Hi. I'm new to this group. I'm coming here because I have a situation that I can't figure out on my own. As I said, I own a 2012 Infiniti G37 coupe that has 55,000 miles on it with no rust or accidents. I purchased the car last year (2024) when the car had 41,000 miles on the car. Even though I love to drive fast, I never really pushed the car and I was impressed with the smalls power gains that I would get whenever I accelerated. But, even with the gains, it was strange to me that the car never felt like it was pulling like a 330HP V6. So, a friend of mine, who also owns a G37 coupes (with way more miles on it) recently drove my car and told me that I have significant power loss and that my car might not even be putting out 250 HP right now. Without a dyno, there's no sure way to measure my horsepower on my car right now, but I'm certain that my car is nowhere near as fast powerful as it should be.

I'd like to drive my car the way it was intended to be driven (with the 330 HP). My car starts up just as it should normally. It idles perfectly, has no CEL, no engines noises like clicking or tapping or anything like that. Except for the lack of 'pressed in your seat' acceleration that I'm supposed to be getting, the car feels like it's a new car.

Can anyone make suggestions about what I should do to try and figure out why my car isn't making power? I know it's a stab in the dark, but if there was anywhere that I could get help resolving this problem, it would be here. Anything you guys can offer would be a great help and thank you in advance.

 

Not a whole lot of info to go on here, besides, "I don't know whats happening".

Assuming you have no Check Engine light, there are a few items to consider:
1) Have you checked for any stored codes?
2) Has all regular maintenance been performed? Things like regular oil changes are obvious, but have you ever cleaned the throttle bodies?
3) How old are the spark plugs?
Regular maintenance is what keeps a machine running as it was intended to run.
If all of the above items seem good, a simple remedy may be to reset the ECU. There is a reset procedure but its easier to just disconnect the negative battery terminal and let the car sit over night. The next morning, reconnect the terminal and the ECU will have reset. Note you may have to reset the auto-up/down feature on your windows after this reset.

All of the suggestions above are well documented on the forum --- search is your friend in this case.

Good luck in trying to figure it out!

 

What @dwb993 said.

Something very simple to try is putting the transmission in sport mode and then punching the throttle. The transmission is very slow to downshift for fuel economy reasons in regular drive. I've made it a habit to either be in sport mode, or to downshift a gear or two with the paddles when I need/want to accelerate hard.

 

Thank you for all of the great suggestions! I'll be back with the results in the next few days.,

 

-2012 Infiniti Coupe Journey AT, 55,800, second owner (no accidents through Carfax), synthetic oil changes every 5,000 miles

As an update, through OBII, I checked my vehicle and there are no codes (or stored codes for the vehicle at all). Even though my car only has 55,000 miles on it, I had the mechanic take a look at both my spark plugs(, which I had them change,) and my coil packs, which are both in great condition given the mileage. There's been no change (increase) in my horsepower or in at least what I think is less horsepower.

Just to get an idea of what my 0 to 60, I measured it with an app, even though they're not perfectly accurate, and I measured 0 to 60 in around 6.7 seconds. (I know that there are some pros in this forum, but I am not. But if I had to do an estimation of what I think my car is putting out right now, I would say it feels closer to between 230 to 250 [rough guess]).

If you think just taking my car to an Infiniti dealer to see what the problem is, I can do that. But, like most people, I don't trust most mechanics.

 

See that you have the oem red air filters.

 

Did you reset the ECU? That should have been done before you took it to a mechanic.

Throttle bodies are fairly easy to clean. The DIY is here somewhere.

May also want to grab a can of MAF Cleaner from your local autoparts store and remove the sensors from the intakes and give them a good clean. As mummy2 suggests, make sure your air filters are clean and in good condition.

 

Google shows this regarding performance:

• Performance: 0-60 mph in approximately 5.7 seconds (Sport coupe), according to Edmunds.

Sounds like your car is not far off of those numbers.

 

I do have the OEM red air filters and I've changed both of them within the last 2,000 miles.

 

I have not reset my ECU. I could try that though.

 

Without other metrics to truly measure the performance and compare, its honestly rough to say if you are truly at a "loss of power".

Have you driven your friend's car to compare?

I'm not very good with the 0-60 runs. I remember I tried it using the draggy and I got 6.06 seconds and that's with mods.

Have your friend also do a 0-60 run to compare to yours.

 

Try and run some fuel injector cleaner through it. Then, get a scan tool that can check your fuel trims. If your fuel trims all over the place it could indicate something like a vacuum leak. Pull the live data from PID info, but you need a decent scan tool for that. You might be able to spot a swing in numbers representing something.