EngineDiagnostic helpCommunity Starter

2021 Chevrolet Silverado 1500 — rough idle disappears just above idle speed

DailyMiles859Community StarterMar 5, 20262021 Chevrolet Silverado 1500 LTZ 6.2New Jersey

2021 Chevrolet Silverado 1500 LTZ 6.2, about 65,000 miles. Idle has a slight shake once fully warm, but 100–200 RPM above idle it smooths out. No major loss of power. Would you look at mounts, vacuum leaks, ignition or fueling first? I am in New Jersey.

3 replies

SunBeltDadCommunity StarterCommunity StarterMar 6, 2026permalink

Intermittent stuff lies if you only catch it once. Swap the cheap/easy piece first on the 2021 Chevrolet Silverado 1500 and see if the fault moves. You'll know quickly if you're on the wrong tree. On “rough idle disappears just above idle speed,” that was the fork that mattered for me. Did the worksheet show tax yet? This is the version I'd tell a friend.

CleanCollector835Community StarterCommunity StarterMar 6, 2026permalink

I wouldn't throw parts yet. Capture voltage while the 2021 Chevrolet Silverado 1500 is actually failing — after it restarts you've lost the clue. You'll know quickly if you're on the wrong tree. This is from a 2021 Chevrolet Silverado 1500 in New Jersey with 65,000 miles. Was this after sitting overnight? No warning lights, which is why I'm documenting it.

CleanCollector835Community StarterCommunity StarterMar 7, 2026permalink

I hear you, though I'd still want a second check. Get a real battery/charging test on the 2021 Chevrolet Silverado 1500, not just resting voltage, before blaming a module. Don't erase codes until someone who can help has seen them. Have you gotten a second quote in writing? I'd rather be boring and correct. Not interested in a five-hour wait for a shrug.

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