I have a 2010 chevrolet silverado , 5.3 liter v-8 and 6-speed transmission. A t 7200 miles the performance started going down hill. It started hesitating on acceleration, erratic shifting, loss of power, idle fluctuates, gas mileage has diminished and even the exhaust tone has changed, it sounds like it has an after-market muffler. Yesterday I tried to pass a slow vehicle hit the passing gear and it almost stalled on me. what do you think could be the problem?

SOURCE: 2001 chevy monte carlo power loss

change fuel grade.if that dont do it. i reccamend a tune up

SOURCE: loss of power

You should have your cat. checked make sure there is no restrictions in your exhaust system.

SOURCE: Transmission Slipping?

Putting it in four wheel drive does not eliminate the transmission. Honestly, it sounds like the transmission is on it's way out. A 4l60e in one of cars was acting the same way. It required a rebuild.

SOURCE: 2004 Kia Rio - sputters and hesitates when going

IT COULD BE DIRTY CLOGGED FUEL INJECTORS OR BAD SPARK PLUGS + WIRES STOPPED UP AIR FILTER. BUT HAVE CAR SCANNED IT COULD BE MASS AIR FLOW SENSOR OR VOLUME AIR FLOW SENSOR.COULD BE MANY THINGS.

SOURCE: Loss of power on acceleration. Put new fuel

Check the catalytic converter, I have the same problem, replaced fuel filter, and crank position sensor, didn't help although the fuel filter was dirty. The car has no power, engine knocks horribly when trying to accelerate up a hill/on ramp. Starts, idles good, lousy power off a stop (should sqawk tires before traction control kicks-in)