2009 Chevy Cobalt Low on Power

[Bob5150]

I have had my 2009 Chevy Cobalt (2.2L automatic) for 4 years, bought in April 2022 with 145k miles.

It currently has 189k miles, and in the past month or so, I have noticed that it feels somewhat low on power. It was never a "fast" car, but always felt like it had adequate power.

As it sits currently:

-Rear drums and shoes were replaced 45k miles ago

-Front brake pads are getting close to ready to be replaced, within the next 10k miles or so

-Air filter has 15k miles on it

-Tires are all inflated properly, matching set, kept rotated

-No check engine light, and no codes stored according my little handheld scanner

-Fuel pump was replaced about 20k miles ago

-Car is due for an oil change in a thousand miles, but I have never noticed a change in performance before when close to being due (every 5k)

-Car starts right up with no excess cranking or anything like that

-I have been running the A/C sometimes on hot days, which I know can add more load to the engine, but again, have never felt a lack of power before

-I have gone through several tanks of gas, I always get gas from the BJ's gas station near me, which sells tons of fuel, so I imagine the fuel is always fresh


The only thing I can think of right now is the spark plugs, which I replaced when I got the car, 45k miles ago. The manual calls for replacement every 100k miles, so technically they should be fine, but I don't know where else to start. Perhaps aftermarket plugs don't last as long as the originals? I don't know what brand they are, just whatever the recommended plugs from Advance Auto.

Any thoughts or suggestions would be greatly appreciated, thank you.

 

[JTK]

At this age/mileage, maybe the catalytic converter is plugged?

 

[Bob5150]

At this age/mileage, maybe the catalytic converter is plugged?

I had the exhaust repaired last summer (flex pipe and the pipe near the muffler rusted off), but even as I'm typing this, I guess that has nothing to do with the catalytic converter possibly being plugged.

Wouldn't that normally set a check engine light?

 

[JavierH19]

What plugs, If they were counterfeit which happens even at local parts stores due to scum bags returning fake junk they know is fake that might be the issue. Someone on here saw that at the store they worked at. Other than that I wonder if the maf isn't metering right. Unplug and drive it for a little as the the operating characteristic of its default logic they usually revert to when it's not metering might show something. Also check the air filer just in case some rat or squirrel didn't mulch it and clog the maf. Saw that with a friends farm truck when trying to help him start it.

 

[The_Eric]

I had the exhaust repaired last summer (flex pipe and the pipe near the muffler rusted off), but even as I'm typing this, I guess that has nothing to do with the catalytic converter possibly being plugged.

Wouldn't that normally set a check engine light?

Not always. I've had them be noticably down in power due to a plugged cat with no CEL

 

[melk]

Have you got a basic scanner that will read fuel trims? A bottle of Redline in the next tank of gas can’t hurt.

 

[ripcord]

There are way to many variables to be able to begin to diagnose this without more info. I would suggest checking to see if there are any Cobalt forums to look for common issues with your year and model.

 

[zzyzzx]

Post the brand and model number of the scanner that you are using for our review and criticism.

 

[SatinSilver]

Give it one more tank of gas since summer blend was required by 6/1.

 

[ripcord]

I suspect the OP just switched from heavy winter boots to light summer shoes...

 

[bullwinkle]

Any rattles on start up? Those Ecotecs can jump time on you... (Of course, my experience is with the older 2.2 L61 dragging around a Vue, so speed is not familiar)

 

[nascarnation]

Plugs easy to access on these and do a quick compression check while you're in there.

 

[97prizm]

I have had my 2009 Chevy Cobalt (2.2L automatic) for 4 years, bought in April 2022 with 145k miles.

It currently has 189k miles, and in the past month or so, I have noticed that it feels somewhat low on power. It was never a "fast" car, but always felt like it had adequate power.

As it sits currently:

-Rear drums and shoes were replaced 45k miles ago

-Front brake pads are getting close to ready to be replaced, within the next 10k miles or so

-Air filter has 15k miles on it

-Tires are all inflated properly, matching set, kept rotated

-No check engine light, and no codes stored according my little handheld scanner

-Fuel pump was replaced about 20k miles ago

-Car is due for an oil change in a thousand miles, but I have never noticed a change in performance before when close to being due (every 5k)

-Car starts right up with no excess cranking or anything like that

-I have been running the A/C sometimes on hot days, which I know can add more load to the engine, but again, have never felt a lack of power before

-I have gone through several tanks of gas, I always get gas from the BJ's gas station near me, which sells tons of fuel, so I imagine the fuel is always fresh


The only thing I can think of right now is the spark plugs, which I replaced when I got the car, 45k miles ago. The manual calls for replacement every 100k miles, so technically they should be fine, but I don't know where else to start. Perhaps aftermarket plugs don't last as long as the originals? I don't know what brand they are, just whatever the recommended plugs from Advance Auto.

Any thoughts or suggestions would be greatly appreciated, thank you.

My dodge neon had this happen. The e brake cable had stretched causing dragging on the rear drums.

 

[clinebarger]

Watch the Engine Load PID during a WOT run above 4500 RPM or so should read 80-100%.....Lower readings could indicate a restricted exhaust.
The Engine Load PID is a pretty accurate indication of volumetric efficiency (Air in, Air out).