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Ask Tool Hut Your Own Question
Tool Hut
Tool Hut, ASE Certified Technician
Category: Chevy
Satisfied Customers: 494
Experience:  Owner of a mobile diagnostics company assisting auto technicians with difficult vehicles
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Surging at steady speed of 35 to 40 put new throttle body

Customer Question

surging at steady speed of 35 to 40 put new throttle body and valve body
JA: How many miles are on the car? Have you noticed any leaks lately?
Customer: 74000 miles no leaks
JA: What is the model/year of your Chevy?
Customer: 2007 chevy cobalt
JA: Are you fixing your Cobalt yourself? What have you tried so far?
Customer: throttle body and valve body
JA: Anything else you want the mechanic to know before I connect you?
Customer: that's it
Submitted: 2 months ago.
Category: Chevy
Expert:  Ron replied 2 months ago.

Hello. My name is ***** ***** I am happy to assist you today. Give me just a moment to review your post, and I'll be right back with the help you need.

Expert:  Ron replied 2 months ago.

Has the computer system been scanned to see if there are any fault codes setting?

Expert:  Ron replied 2 months ago.

Can you answer the last question I posted, Has the computer system been scanned to see if there are any fault codes setting?

Customer: replied 2 months ago.
No codes
Expert:  Ron replied 2 months ago.

Okay there is one known issue with a surge your describing with the 2007 Cobalt and GM has released a service bulletin dealing with it that calls for reprogramming the TCM ( transmission control Module) . I have enclosed it in the link below as I suspect it may apply to the problem you are having. Have a look and post back if you have more questions and or need more help.

https://dl.dropboxusercontent.com/u/104923897/Surge%20Sept%2021.pdf

Customer: replied 2 months ago.
Has that done at Chevy dealer no difference
Expert:  Ron replied 2 months ago.

In most case if the problem is a computer control issue there would be a fault code and or codes setting, are you sure there are no fault codes setting?

Customer: replied 2 months ago.
hey ron dealer already did update
Expert:  Ron replied 2 months ago.

Okay with out any fault codes to go by I have no further information. I will open the post back up for you and perhaps someone else has something else to offer.

Expert:  Tool Hut replied 2 months ago.

Hi, My Name is ***** ***** for posting your question to just answer. I am a independent contractor for just answer. ASE Certified Master Auto Technician with 20 years experience. I am confident we can resolve your problem together.Please remember I don't know your skill level. I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies to get to a satisfactory resolution.There will probably be some equipment needed for a proper diagnosis. If you are not comfortable with this or do not have any test equipment please let me know ASAP. I also give you all of the information you may need in good faith expecting a positive rating. I am not compensated for my time until you leave a positive rating. Your rating should be based on the service you received.

Do you have a scan tool with DATA?

Customer: replied 2 months ago.
I have put new valve body and throttle body and tcm update
Expert:  Tool Hut replied 2 months ago.

OK. If you lightly hold the brake pedal when the surge starts does it get better?

Customer: replied 2 months ago.
I will try that
Expert:  Tool Hut replied 2 months ago.

OK. let me know results

Expert:  Tool Hut replied 2 months ago.

Hello, I have not heard from you in a few days. Do you still need assistance? I also noticed you haven't left a rating. I have assisted in good faith and am only compensated when you leave a positive rating. Please let me know if there is anything else you need to leave a positive rating. Conversations can always continue after a rating is received.