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Bill, Chevy Technician
Category: Chevy
Satisfied Customers: 1776
Experience:  GM Certified Master Technician
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Chevrolet 2500HD: My 2004HD duramax lost power on the highway

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My 2004HD duramax lost power on the highway doing 70 when I tried to accellerate- no response- slowed down a bit then was able to maintain 62-65 mph the next 30 miles home- 2000 rpm seemed to be the max- ran fine as long as I kept it 2K rpm or less- any ideas?

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Did you get a check engine light on and/or have you had it scanned for stored fault codes? Do you have any modifications to the vehicle and have you had your air and fuel filters changed any time in the recent past?






Customer: replied 2 years ago.
No check engine light appeared-I have not changed the filters recenly-

There is likely a type B fault code stored which requires two failures to set the light on. I would recommend you have it scanned for any faults that may be stored initially. As simple as it sounds, fuel and air filters are by far the most common cause of this concern on the duramax. Huge amounts of air go through the engine and they are much more sensitive to restrictions in the air filter and fuel filters than any gasoline engine. Probably 85% or the concerns I've had with these have been fuel and air filters. I would recommend changing both, having it scanned and clearing any stored faults and if there are any, reply here. I know it sounds so very basic but believe me it is the most common cause of this concern.




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Customer: replied 2 years ago.
Can there be separate codes related to the transmission that wouldn't cause a warning light?