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Jared D
Jared D, ASE Certified Technician
Category: GM
Satisfied Customers: 1733
Experience:  Shop Supervisor at County Fleet
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PO301. PO324, PO446 CO561, SURVICE TRACTION CONTROLL MOTOR

Customer Question

PO301. PO324, PO446 CO561, SURVICE TRACTION CONTROLL MOTOR KNOCKING
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: Couple weeks just been driving it easy
JA: What is the model/year of your GM?
Customer: 2012 chevy 2500 hd z71. 6.0 gas
JA: Are you fixing your 2500 yourself? What have you tried so far?
Customer: Yes new plugs and wires
JA: Anything else you want the mechanic to know before I connect you?
Customer: Thats about it
Submitted: 2 months ago.
Category: GM
Customer: replied 2 months ago.
Motor only knocks when it is reved over 2500rpm, idles smooth
Customer: replied 2 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Jared D replied 2 months ago.

What you describe sounds like a bad rocker arm (the are called valve keepers sometimes) or a bad lifter. Does it sound like the noise is mostly from the top end of the engine?

Have you performed a compression test yet?

Customer: replied 2 months ago.
thats where i think its coming from Thats what i was afraid of it has 227500 miles on it
Expert:  Jared D replied 2 months ago.

Whenever I see knock that only occurs above 2500 RPM or so it's almost always a worn rocker arm. They aren't terribly hard to replace. You have to remove the valve cover and install the new rocker on the failed cylinder. From the look of those codes it's most likely cylinder #1. Do you plan to tackle it yourself?

Customer: replied 2 months ago.
I have rebuild a couple engine before
Customer: replied 2 months ago.
I figured it was a bad valve cam shaft it would back fire correct
Customer: replied 2 months ago.
Thank you
Expert:  Jared D replied 2 months ago.

If it was a bad camshaft it would probably misfire on all cylinders and it would just be wimpy rather than backfire.

Expert:  Jared D replied 2 months ago.

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Expert:  Jared D replied 1 month ago.

Please don't forget to rate- that's how Just Answer compensates us for our time.