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Audi · Known Issues

2021 Audi RS4 Problems: 1 Known Issue

2021 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated September 2026

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Vehicle data and repair guidance on this site are compiled with AI assistance and may contain errors. Always verify with your service manual or a qualified mechanic.

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According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2021 Audi RS4 has 1 documented issue. None of the listed issues is rated critical; this is not a complete reliability assessment. DIY maintenance guides at au7o.io.

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All 1 Known Issue

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On the 2018-2023 Audi RS4 2.9T, audi TSB 2075530/1 documents that deposits in TFSI inlet ports and inlet valves can cause rough idling after a cold start and sporadic misfires, especially on vehicles used mainly for short trips. For the 2018-2023 RS4 2.9T record, this supports a symptom-triggered diagnosis and repair path; it does not establish that every vehicle has a chronic defect or needs cleaning at a fixed mileage.

This issue also affects: Audi S8, Audi A4, Audi A1

Common Symptoms

  • Rough idle after a cold start
  • Sporadic engine misfire recorded in event memory

How to Fix

Confirm the cold-start complaint, review the engine-control-unit event memory and verify inlet-port or inlet-valve deposits before cleaning. When that condition is confirmed, Audi TSB 2075530/1 directs the shop to remove the intake manifold or compressor and clean the inlet valves and ports by walnut blasting; the cylinder head remains installed. The cited Audi guidance does not support a mandatory 60,000-mile interval, a fixed price, dual catch cans, additive at every oil change, a 5,000-mile oil interval or a drive-hard prescription. Do not buy a catch can or cleaning product solely from this card.

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Other Audi Models

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Frequently Asked Questions

What are the most common Audi RS4 problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2021 Audi RS4 has 1 documented issue. The documented issue is: 2018-2023 RS4 2.9T Cold-Start Misfire from Confirmed Inlet Deposits. None are rated critical, but regular maintenance is recommended.

Is the Audi RS4 reliable?

The 2021 Audi RS4 has 1 known issue compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. None of the matching records is rated critical; this is not a complete reliability assessment. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

What is the 2018-2023 Audi RS4 2018-2023 RS4 2.9T Cold-Start Misfire from Confirmed Inlet Deposits?

Audi TSB 2075530/1 documents that deposits in TFSI inlet ports and inlet valves can cause rough idling after a cold start and sporadic misfires, especially on vehicles used mainly for short trips. For the 2018-2023 RS4 2.9T record, this supports a symptom-triggered diagnosis and… Severity: medium.

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data compiled from NHTSA recalls, manufacturer TSBs, automotive forums, and AI-assisted research. No aggregated owner-report counts available for this vehicle yet.