I have researched research and research. nothing!

I have a 2012 impala LTZ 3.6. My car runs like crap. The car lacks power, If I mash the gas, the rpms shoot up to 4.5k and the car slowly gains speed to about 40 and then will struggle to pass that mark. on the highway, if i'm going 60 and I press the gas harder, the rpms shoot up and the car will take forever to gain speed. If the car down shifts going up a hill and I continue to press the gas, the car will go into engine reduced power and kick on the traction control light, and service stablink.
The car idles and starts just fine
There are no check engine lights on

I have changed the MAF, MAP and throttle body/TPS. I had the cats checked by a muffler shop and they told me they were in good shape.

Any idea?

 

Sounds like it might be a transmission issue to me, but could be fuel injectors. However it might be good to run a compression test. How many miles are on your Impala?

 

The car has 130,000 miles. It shifts and down shifts just fine. If I drive it normal, it will drive/shift just fine but I can tell it lacks power. The only time it doesnt have power is when I mash the gas.

If I start at 10 mph and mash it, the rpms shoot up and the car slowly goes to 40 and then wont push past that.

 

It could be a bad accelerator pedal that is not sending your throttle position to the TB sensor properly, or might be a bad TPS on the TB, perhaps.

It could even be a lousy battery or a weak alternator. I'd have the battery checked out first, by a professional as the auto-parts stores battery testers
are fairly lousy and selling a new battery is on their lists of things to sell, which is everything of course..

BTW, what you are experiencing is not uncommon for the 2011 Impala 3.6 liter at all. Try the "car-complaints" page to see what I mean.