2009 Maxima rough idle and loss of power
 

I have a 2009 Maxima with 173,000 miles on it. About a month ago, I noticed that the engine would shimmy or buck when I would travel at a consistent speed of 70 mph. Shortly after that, I noticed the engine would idle high (1,200) and run rough (sounded like a truck running). I noticed loss of power at normal accelerations and seemed like the engine was missing. Thinking that the coil packs were going bad, I replaced them along with the plugs. Still the same issue. I also replaced the mass air flow sensor and still nothing. I did the idle relearn about 20 times and still no help. Has anyone else figured out how to fix this issue without having to go to the shop and spend mega $$??

Is your Check Engine light on?

You could possibly have a clogged/defective fuel injector or a vacuum leak someplace...try running a can of good fuel injector cleaner through it and see if that helps at all. More labor intensive, but injectors can also be tested to see if they're functioning properly. Also check for air leaks around the intake manifold or perhaps if a vacuum hose is disconnected.

My light is not on. It seems to come and go now. I have run several bottles of Berryman's through the tank and it seemed to help. Yesterday I changed the CVT fluid and the belt. It felt nearly perfect after I drove. This morning, however, it felt jerky around 55-70 mph, but not as severe as it was prior to the fuel treatment, fluid and belt change.

Did you use OEM coils? Plug a scanner in and look for any stored fault codes.