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2020 Tahoe 5.3L Engine Ticking Noise and Misfire

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Mike T. · rep 0 · May 25, 1:39 AM · 1 replies · solved · Question

Vehicle: 2020 Chevrolet Tahoe LT 5.3L V8

I'm reaching out because my 2020 Chevrolet Tahoe LT with the 5.3L V8 engine is making a really concerning noise. It has about 55,000 miles on it. For the last month or so, I've noticed a distinct ticking or tapping sound coming from the engine, particularly noticeable on cold starts and sometimes when idling.

Recently, the Check Engine Light came on, and I got a P0304 code, indicating a misfire on cylinder 4. I've heard about issues with the AFM/DFM system on these engines, and I'm wondering if that's what I'm dealing with. Is this a common problem, and what's the typical fix for it?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 1:39 AM

0

ClearTheCode admin answer:

The ticking noise combined with a P0304 misfire code on your 2020 Chevrolet Tahoe 5.3L V8 is a strong indicator of an issue with the Active Fuel Management (AFM) or Dynamic Fuel Management (DFM) system, specifically related to lifter failure. This is unfortunately a well-documented and common problem on GM's V8 engines equipped with these fuel-saving technologies.

Common Causes:

  1. AFM/DFM Lifter Failure: The hydraulic roller lifters used in the AFM/DFM system can fail due to various reasons, including oil pressure issues, manufacturing defects, or debris. When a lifter collapses or sticks, it can cause the associated cylinder to misfire (as seen with P0304) and create a loud ticking or tapping noise as the rocker arm loses proper contact with the valve stem.
  2. Oil Quality and Maintenance: While not the sole cause, infrequent oil changes or using incorrect oil viscosity can exacerbate wear on these sensitive lifters.
  3. Oil Pressure Issues: Insufficient oil pressure can prevent lifters from properly functioning, leading to their collapse.

Diagnostic Steps & Potential Fixes:

  1. Confirm Lifter Failure: A technician will typically use a stethoscope to pinpoint the source of the ticking noise. They may also perform a compression test or inspect the valve train components (rocker arms, pushrods) to confirm a collapsed lifter.
  2. Retrieve All Codes: While P0304 is present, ensure no other misfire codes (P030x) or related engine codes are present.
  3. Repair: The most common repair for a failed AFM/DFM lifter involves replacing the faulty lifter(s) and often the associated cam lobe if it's been damaged. In many cases, it's recommended to replace all AFM/DFM lifters on that cylinder bank, or even all of them, along with the valley cover (which contains the AFM oil manifold) and potentially the camshaft itself if there's damage.

When to See a Shop:

  • Immediately: A ticking noise combined with a misfire code indicates a serious internal engine problem. Continuing to drive with a collapsed lifter can lead to further, more extensive damage to the camshaft, cylinder head, and potentially other engine components. Get your Tahoe to a qualified Chevrolet dealership or an experienced independent mechanic specializing in GM V8 engines as soon as possible. This type of repair can be costly, so inquire about any extended warranty or recalls that might apply to your vehicle.
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