How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chris (aka-Moose) Your Own Question
Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Car
Satisfied Customers: 47963
Experience:  16 years of experience
Type Your Car Question Here...
Chris (aka-Moose) is online now
A new question is answered every 9 seconds

Nov. 2011, GM dealer changed my 2006 H3 Hummers catalyst and

This answer was rated:

Nov. 2011, GM dealer changed my 2006 H3 Hummer's catalyst and manifold because it was bended and it had less power + check engine light on. This morning, March 1st 2013, I decided to go back to the dealer because since two weeks, I could hear a kind of whistling everytimes I was accelerating and the engine light was going on and off. Mechanics told me not to consider it. On computer they told me that I had a problem with manifold and catalyt which were once again bended + blocked in a way - I don't understand how this could be twisted - they told me that it has to be changed because of a defected of the previous exhaust manifold. Check engine light still on even after that. I didn't pay because of my warranty but this one will end in June 2013. Is it a common problem on this vehicle - I do have only 57 000 miles, and I wonder if I should keep it? They also told me that the mix (oxygen and gas) was poor - they can't find the problem. What should they check to solve the problem?

Hello, I'm Chris. Thanks for visiting Just Answer.


Converter alone failure is not common on this model but other causes not addressed which result in converter failure are common. These things need to be checked for both your air/fuel mixture and for your concerter issues, fuel pressure regulator leak, engine misfire, dirty fuel injectors, coolant consumption, misreading MAF sensor, vacuum leaks.


You mentioned your converters are bending, this sounds more along the lines of faulty engine mounts allowing the engine to torque to much to the side when under load, thus twisting the exhaust and damaging the exhaust system.

Chris (aka-Moose) and 9 other Car Specialists are ready to help you
Hello again Chris here.

It has been a few days, so I am just checking in with you to see if you still need help, and if not to say Thanks.

Thanks Chris
Customer: replied 4 years ago.

Sorry for not answering earlier, I went to the garage, and got the spark plugs, the PCV hose and the crank sensor changed and now it seems ok. So thanks for your suggestions, I will keep it in mind if ever something else occur. Thanks,



Glad it worked out.