My wife has regularly been complaining about how the car won't "pick up speed" and feels "bogged down" especially going even slightly up hill on the highway. It does feel a lot better in Sport Mode, but kills the gas mileage. I understand it's a big heavy car paired with only a V6, but what engine modifications(within reason) would you guys recommend to add that extra bit of power so it doesn't feel so bogged down?

Best thing I can recommend is push the gas pedal down. Yes gas mileage will go down. But the car won't slow down. Why make all the modifications to produce more horsepower. When you already have enough horsepower just use more gas.

If she drives it a bit harder. The transmission will learn new shift points.

Maybe you should try the ECU Reset before anything else.

is it possible she is driving in economy or snow mode instead of standard or sport
both snow and economy really don't allow much acceleration
Mazz

I think the VQ engine has great power, even when going uphill. How many miles are on the car and how are you with routine maintenance? Something as simple as dirty air intake filters could be the cause of the acceleration issue. Is it misfiring? Do you have any codes? Or do you think your wife expect it to perform like a 500hp car?

I've done the ECU reset in the past and can try it again. Also, I've dropped in K&N Air Filters and just purchased NGK Laser Iridium spark plugs. She always drives in "Normal" as she doesn't like the rev matching feature when braking in "Sport". I've had Infiniti reprogram the TCM and ECM per ITB12-021B and all maintenance items are up to date. I only use Synthetic oil with K&N Oil Filters and premium gas. I've even paid to have Infinti do the "Emissions Service" and have Seafoamed the car so I'm fairly certain carbon buildup isn't an issue. It does have about 120K, but she was used to driving a crappy 05 Altima and never complained.

Debonair, Thanks for the ECU reset suggestion.

I just got into a 2012 M37x with 16,058 miles 3 weeks ago and was impressed with the stats. v6 with 330 HP. Def an upgrade from my 2003 Acura RL. But it seemed to lag and hesitate when down shifting at highway speeds.

I learned about the transmission reprogram from this site and took it to the dealer to have it serviced. They performed the update but it still was not punching like a 300 plus hp car should. Was having serious regrets because I wasnt confident merging onto highway traffic. Stomp the gas and the tach would jump to 5000rpm hesitate and then kick in. Once it kicked in it hauled but that hesitation made me nervous. Figured a car like this should have power to tap and in spades. I went to BMW dealership to see what I could get for the car. Looked into a 535i xdrive (sorry temporary moment of weakness). Didnt make sense money wise so I kept the M.

Glad I did and saw this ECU reset. Definitely improved the hesitation. Power on demand and drives like a dream.

Feels like Ive learned so much in a few short days. Thanks for all the great info. Hopefully as I get the hang of this car I can contribute to the forum.