2008 Cobalt LS Problem with Acceleration/lack of Power/hard Shifting - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
Problems and Service Talk about any mechanical problems you are having

 
LinkBack Thread Tools Display Modes
post #1 of 10 (permalink) Old 08-10-2012, 03:03 AM Thread Starter
Newcomer
 
Join Date: Aug 2012
Posts: 4
2008 Cobalt LS Problem with Acceleration/lack of Power/hard Shifting

Hey guys,
I've been having a problem with my cobalt for last year or so and it's been getting progressively worse to the point that I can no longer ignore the issue.

When I accelerate, my RPMs fluctuate and I feel a jerky feeling. As I continue to accelerate, the RPMs will drop a couple hundred RPMs about every second or so causing my car to feel like there's a slight "buck" to it. Similar to (although not as dramatic) the feeling of pressing on the gas, letting off for a sec and then giving it gas again over and over again. The problem sometimes persists when I have a constant RPM (like I'm maintaining speed). It's like the fuel injectors aren't injecting the fuel properly. The power definitely doesn't seem optimal either. Neither does the fuel economy (although I haven't tested it, it just seems like it's not as good) It doesn't matter what gear I'm in or how fast I'm going. I noticed the problem about a year ago, but never did anything about it. It didn't seem like a real big issue but it's been getting worse. Took it to the dealer and they want $130 just to diagnose. I've run injector cleaners, etc but to no avail. I'm hoping someone here has had a similar issue and can shed some light?

Another problem I'm having is that my transmission feels like it's shifting hard especially in city driving. At times I get a noticeable jerk when it shifts. Doesn't matter what gear its in. That also has been getting worse.

I've never had a check engine light on, and I've also been very faithful in oil changes.

Any advise??

Ps : mileage is about 86000, and I guess you can consider me a "hard driver" a majority of the time.
Cshoffie is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 08-10-2012, 06:13 AM
Super Moderator
Staff Alumni
YourCobalt of the Month Winner


 
Blackbalts's Avatar
 
Join Date: Aug 2011
Location: Burnsville, Minnesota
Posts: 5,481
Garage
Any other maintinance other than oil changes? Tranny flush should have been done at least once by now. Plugs? Fuel filter? Clean the throttle body?


05 Mitsubishi Evolution 8
05 Chevy Cobalt LS (RIP 7/13/2013)
99 Nissan Altima GXE (Daily)
99 Subaru Legacy (Daily)
07 Jeep Liberty Limited (No longer the tow truck for the balt )

If you have questions and I'm not on please PM, notifications go straight to my phone 24/7.

My Showoff
Join YC on FB
Syndicate of Tuners.com
Blackbalts is offline  
post #3 of 10 (permalink) Old 08-10-2012, 08:49 AM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
Quote:
Originally Posted by Blackbalts View Post
Any other maintenance other than oil changes? Tranny flush should have been done at least once by now. Plugs? Fuel filter? Clean the throttle body?
May also add MAF clean, and clean the engine/transmission ground(G103), TCM, ECM ground(G105) on drivers side strut tower.

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly
Coby7 is offline  
 
post #4 of 10 (permalink) Old 08-10-2012, 09:25 PM Thread Starter
Newcomer
 
Join Date: Aug 2012
Posts: 4
I spent the day today doing some tune ups on the car. I replaced the spark plugs, replaced both air intake and cabin air filters and cleaned the intake system including scrubbing the throttle body.

I got some seafoam intake cleaner from Auto Zone and used that to clean both the MAF (sprayed it to heck) AND throttle body.

Also noticed that the dipstick was saying I was down on oil below minimums and so I topped off the oil (its due for a change soon anyway). I thought it a bit odd that the oil was so low as I've never seen any evidence of leakage...

Did a test drive after, same old issue. Not as much power and acceleration is choppy.

So my guess is that it has nothing to do with the intake system. So now I'm back to my original theory about the fuel system. My car has CA PZEV equipped so the filter is out of question (being "unservicable" - not sure how filters don't need to be changed but ok..).

Any other theories? Pleeeaase?
Cshoffie is offline  
post #5 of 10 (permalink) Old 08-10-2012, 11:39 PM
Veteran
 
Join Date: Jan 2012
Posts: 584
Garage
Change the oil.

[Insert signature here]
white balt is offline  
post #6 of 10 (permalink) Old 08-11-2012, 05:06 AM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
Still no engine codes? Did you clean the TCM ground terminal?

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly
Coby7 is offline  
post #7 of 10 (permalink) Old 08-11-2012, 12:36 PM Thread Starter
Newcomer
 
Join Date: Aug 2012
Posts: 4
The guy at auto zone said that unless I have a check engine light on then there's no codes being thrown. So my guess is that there's no codes since I don't have a check engine light.
I'm trying to find where then TCM ground is to clean it. Where is it exactly?
Cshoffie is offline  
post #8 of 10 (permalink) Old 08-12-2012, 07:44 AM
Newcomer
 
Join Date: Jul 2010
Posts: 8
Cshoffie - Im having the same problem not much power and acceleration is choppy.
Im very interested if anyone else has answers.

I might try flushing the tranny fluid.
Kemal306 is offline  
post #9 of 10 (permalink) Old 08-12-2012, 08:07 AM
Super Moderator
YourCobalt.com Premium Member


 
Coby7's Avatar
 
Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
Posts: 11,820
Garage
This is the grounding point for all engine sensors and also your TCM (G105). Some claim to have cured the hard shifting issue with a simple clean. The tab with wires going left is ground for engine sensors and the tab with wires going right is the ground for "TCM".

Quote:
Originally Posted by Cshoffie View Post
The guy at auto zone said that unless I have a check engine light on then there's no codes being thrown. So my guess is that there's no codes since I don't have a check engine light.
With a good reader you can read pending codes and history without a "CEL"

Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2016 Cocoa Buick Encore 1.4L Turbo auto KL4CJDSB2GB652675
Drives 2016 Sunset Orange Trax LT1 1.4L Turbo auto 3GNCJPSB8GL142716

Never drive faster than your guardian angel can fly

Last edited by Coby7; 08-12-2012 at 08:09 AM. Reason: Typo
Coby7 is offline  
post #10 of 10 (permalink) Old 08-13-2012, 07:56 PM
Chevy Customer Service
YourCobalt.com Premium MemberExpert
 
ChevyCustSvc's Avatar
 
Join Date: Nov 2010
Location: Detroit, Michigan USA
Posts: 794
Sorry that you both are experiencing what sounds like a very frustrating concern! If I can help with anything GM-related (warranty/recall/working with a dealership questions), please get in touch with me via private message (include the last 8 of your VIN and contact information). I wish you the best as you continue on in diagnosing this!

Sarah, GM Customer Service
ChevyCustSvc is offline  
Sponsored Links
Advertisement
 
Closed Thread




Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome