Hello,

Firstly, I hope everyone is safe and well in these crazy times! I have a 2013 G37x Sedan Automatic at 59k miles. I have been on point with maintenance: Across October + Novemebmer 2019, I have changed every single fluid in the car except for the transmission, thanks to the wonderful DIY tutorials on here. I used Nissan fluids for the differentials and transfer case. Also, thoroughly cleaned the MAF/Throttle Body and the PVC's. Changed out air and cabin filters with OEM. Car is bone stock. New battery in November 2018.

However, the other day I was driving the car and noticed that the car was behaving oddly. I then noticed that the RPM's were bouncing around unusualy especially if I let off the gas. Acceleration was also noticeably slower. I inspected the car after and noticed a strange air leak sound coming from the middle left of the engine. However, embarrassingly when I checked the next day I believe that sound could have been the belt and I was just paranoid/mistaken. I also recall I have this rattling sound at idle or reverse, but this time it was much more pronounced, I feel the engine was shaking more then normal at idle. I know the Infiniti cover is on, with the center screw decently tight as I know sometimes air can come out of there from reading on here. The next morning, the RPM's were smooth again with idle steady at 650. However, after the car is warmed up if I hit the accelerator pedal hard, it is almost like nothing happens and there is a delay for 1-3 seconds, and then the rpm suddenly revs high and then the car goes faster. However, it does not accelerate as quickly as normal, normally when I do that at those speeds the car launches like a rocket and my head goes back all while in DS. D is delayed more then normal too, there was a yellow light so I gently hit the accelerator and you can just tell the power delivery is not normal.

I have been reading around so I am planning to reset the ECU, and disconnect the battery for a good 5 minutes. Another thing to note, I have hardly been driving the car this past 2 months with everything. I do drive it every 2-3 days but they are short trips to the store and back. I last filled my gas tank April 28, but I will admit it was at a Shell station that has cheaper prices but it is out of the way where there is not much traffic. My other theory is maybe I have old/bad gas? I plan to fill up at a high traffic Shell/BP station and see if that makes a difference. Also, the weather here has been weird lately, it has been from hot in the day to almost freezing at night, on and off for the last 2 weeks.

One last tidbit, I did do a idle re-learn the other week. I havn't driven car much since then so I wonder if car is just learning again and I am simply confusing the symptoms with that?

Would appreciate any advice. Thanks!

 

sounds like one of the vacuum lines came loose after you cleaned the throttle body. Check all the connections spray soap water on line you think is leaking to see bubbles or use a smoke machine

 

Turned out to be bad gas.I filled up at a popular Shell station this time (I always use Shell) and car has been running great again. The gearing is off every once in a while but think just need to do the old ECU Reset, then drive the car hard to reset it which I noticed I had to do last year.
Thanks for responding, I really appreciate it. I was super stressed with everything going on these days last thing I need is car troubles.