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Ever since I have owned my 2011 Chevy Colorado (from Oct 2015) it has had no next to no power and at
times does not seem to be able to get out of its own way. I have just lived with it for the almost 3 years I
have owned it. However after nearly being hit trying to merge on to a road from an off ramp by a car
that was far enough back that in any other car, I would had no problems merging, I have finally decided
that enough it enough. I need to look into this.

First off, my truck is a 2011 regular cab Colorado (aka the white work truck) with the 2.9l 4 cylinder
engine coupled with the automatic transmission. Other then automatic transmission, CD player, fog
lights, Bluetooth, Onstar and A/C it is a basic truck. The truck had 89,934 miles on when I bought it and
now has about 116,938 miles on it.

Things it does:
If I am coming up to a red light and slowing down and then the light changes to green and I push down
the accelerator it does not accelerate quickly at all. It will eventually come up to speed but it is not a fast
process.However if I floor it then it will take off.
If I am on an off ramp or need to speed up to pass somebody, I have to floor it or else it does not seem
to have adequate acceleration.
It almost seems like I am driving a manual transmission vehicle where I am in a higher gear then what
the speed dictates. It does not bog down but there is no real acceleration when you push the gas pedal
down halfway or less. If I floor it then it gets its act together. If I just let it get up to speed on its own
then it drives fine.
It also seems to sometimes shift sooner then the speed on the speedo seems to dictate. But I am not
sure if this is a GM thing to help with gas MPG
The car originally came from Enterprise Fleet Management. The truck looks like it was regularly serviced
in their care.
The car was bought from a dealer that I am friend with the owner and other folks in it. They said other
then new brakes and tires, the truck looks good and passed my state’s tough vehicle inspection.

Here is what I have done to it:
I have replaced the spark plugs (though the ones that came out looked almost new) with Delco plugs
I have had the transmission fluid replaced(the stuff in the trans looked fresh and there are signs that the
fluid was replaced in the recent past before I bought it)

I took the truck for a ride on a empty back road when I could check how the trans shifts. It seems to shift
fine into all the gears and I can feel the TCC go on. I count 3 shifts and the TCC go on (I am assuming it is
starting out in first gear)
On the highway I can hit 90mph with ease
So I am going to go out on a limb and say the transmission is not the issue and that it works fine.

It just seems like the issue is ether stop and start driving or trying to pull out from a parking lot onto the main road or on an off ramp.

I get no check engine light or codes that don’t turn the check wallet light on.
The truck does not bog down and there is no sputtering or vibrations. The truck idles fine. I looked at the
exhaust system and it does not have a glowing cat and the exhaust seems to have no restrictions

Is there some sensor that I can check to see if this is causing the issue?

Right now as it stands, my 1997 Pontiac Trans Sport van with 700 more pounds(as listed by the placard
on the door) and 5 less horsepower seems like a indy car compared to my truck

Any assistance you can give me is appreciated

Thanks
 

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Start with the basics. Clean the mass air flow sensor, clean the throttle body, and replace the upstream O2 sensor. Confirm there are no vacuum leaks and that the intake manifold to cylinder head bolts are all tight.The O2 sensor has a recommended maximum life of 100,000 miles. I recommend Delco for sensors but Bosch also makes good O2 sensors.
These trucks have "drive by wire" throttles which means the accelerator pedal position sensor (APP) is connected to the throttle body by an electric circuit to the PCM instead of a throttle cable. There is a possibility that your APP which includes two potentiometers may be failing and not commanding the throttle body to respond properly. I am not sure what the best way to test the APP but maybe someone will respond with an answer.
Good Luck!
 

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^ What he said... Check to see if Cat is plugged... Classic symptoms.
 

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^ What he said... Check to see if Cat is plugged... Classic symptoms.
Plugged converter. Loosen the bolts that connect the exhaust pipe to the exhaust manifold enough to allow exhaust to escape. If it runs fine then plugged cat. Id the problem.
 

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If all else fails. Might be the accelerator pedal. They’re electronic and there are pins in the pedal that might not have good connection to the board that’s sent to the computer.
 
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