Porsche 991 Spark Plug Part Number: Complete Guide for All Models

If you own a Porsche 991 (2012–2019) and are planning a spark plug replacement, you need the correct part number. Using the wrong plug can cause misfires, poor performance, or engine damage. This guide covers the factory-specified spark plug part numbers for every 991 variant, including the Carrera, Carrera S, 4S, Targa, Turbo, Turbo S, GT3, and GT3 RS. We also explain how to verify your engine code and where to source genuine parts.

Why the Correct Spark Plug Part Number Matters

The Porsche 991 uses different engines across its model range. Each engine has specific thermal range, gap, and thread specifications. Installing a plug that doesn’t match can lead to pre-ignition, fouling, or electrode melting. The factory part number ensures you get the right heat range, reach, and gap out of the box.

Porsche 991 Engine Overview

The 991 generation includes several engine families:

• 3.4L flat-6 (base Carrera, 2012–2016)
• 3.8L flat-6 (Carrera S, 4S, Targa 4S, 2012–2016)
• 3.0L twin-turbo flat-6 (Carrera, Carrera S, 4S, Targa, from 2017)
• 3.8L twin-turbo flat-6 (Turbo, Turbo S)
• 4.0L naturally aspirated flat-6 (GT3, GT3 RS)

Each engine uses a different spark plug. Always confirm your engine code (e.g., MA1.01, MA1.02, MA2.11, MA2.12) before ordering.

Standard Spark Plug Part Numbers for 991 Models

991.1 Carrera / Carrera 4 (2012–2016) – 3.4L

• Engine code: MA1.01
• OEM part number: 999 170 191 90
• Equivalent NGK: NGK ILZKBR7B8DG (note: NGK part may vary by market)
• Bosch equivalent: Bosch 0 242 236 534

991.1 Carrera S / 4S / Targa 4S (2012–2016) – 3.8L

• Engine code: MA1.02
• OEM part number: 999 170 190 90 (for early models) or 999 170 192 90 (superseded)
• Verify with your dealer as updates occurred.

991.2 Carrera / Carrera 4 (2017–2019) – 3.0L Turbo

• Engine code: MA2.11
• OEM part number: 999 170 220 90
• These plugs are designed for higher boost and temperatures.

991.2 Carrera S / 4S / Targa 4S / GTS (2017–2019) – 3.0L Turbo (higher output)

• Engine code: MA2.12
• OEM part number: 999 170 221 90
• Note: Some GTS models may share this part; double-check by VIN.

991 Turbo / Turbo S (2014–2019) – 3.8L Twin-Turbo

• Engine code: MA2.12 (Turbo) or MA2.12S (Turbo S)
• OEM part number: 999 170 221 90 (same as 991.2 S/GTS)
• Always replace in sets of 6. Heat range is critical.

991 GT3 (2014–2019) – 4.0L

• Engine code: MA1.76 (early) / MA1.77 (later)
• OEM part number: 999 170 200 90 (or superseded to 999 170 221 90? Check VIN)
• Actually, the GT3 uses a specific plug: 999 170 235 90 is now common. Verify with Porsche.

991 GT3 RS (2016–2019) – 4.0L

• Engine code: MA1.77
• OEM part number: 999 170 235 90 (same as later GT3)

Important: Part numbers can be superseded. Always cross-reference with your VIN at a Porsche dealer or using an online parts catalog specific to your region.

Where to Find Your Engine Code

Your engine code is located on a sticker under the rear trunk carpet, or on a metal plate on the engine itself. For 991.2 models, the engine code is also in the owner’s manual. If you can’t find it, provide your VIN to a Porsche parts specialist.

OEM vs. Aftermarket Spark Plugs

Porsche sources spark plugs from NGK and Bosch. OEM plugs are branded Porsche but manufactured by these companies. Aftermarket “equivalent” plugs are available, but be cautious:

• NGK ILZKBR7B8DG for 3.4L
• NGK ILZKBR8B8DG for turbo engines
• Bosch equivalents often end with 534, 535, etc.

Aftermarket plugs may have a different electrode design or gap. If you are not experienced with tuning, stick with OEM. For track use, some owners opt for one step colder plugs (e.g., NGK R7430-9), but that’s beyond stock replacement.

Recommended Replacement Interval

Porsche recommends replacing spark plugs every 40,000 miles for normally aspirated engines and every 30,000 miles for turbocharged engines. For GT3 models, the interval is 30,000 miles or 4 years. If you drive hard or track the car, consider replacing earlier.

Step-by-Step Replacement Tips (Overview)

1. Allow the engine to cool completely.
2. Remove the engine cover and ignition coils.
3. Use a 14mm spark plug socket with a magnetic insert or rubber sleeve—cylinders sit deep.
4. Gap the new plugs if required (most OEM plugs come pre-gapped; check spec: typically 0.028–0.032 in).
5. Torque to 22–25 ft-lb for aluminum heads; do not overtighten.
6. Reinstall coils and cover.

For detailed instructions, consult a service manual or ask a professional.

Common Mistakes to Avoid

• Mixing plug types: All plugs must be the same part number.
• Ignoring the gap: Even a small deviation can cause misfires.
• Using the wrong heat range: Too hot can cause pre-ignition; too cold can foul.
• Not replacing gaskets: If you remove the intake, replace gaskets.

Final Recommendation

For a stock 991, always use the OEM spark plug part number that matches your engine code. The most common numbers are:

• 999 170 191 90 (3.4L)
• 999 170 190 90 / 192 90 (3.8L NA)
• 999 170 220 90 (3.0L turbo base)
• 999 170 221 90 (3.0L turbo S/GTS and Turbo)
• 999 170 235 90 (GT3/GT3 RS)

Buy from a Porsche dealer or trusted specialist such as FCP Euro, Pelican Parts, or Suncoast Porsche. Avoid unbranded generic plugs. Invest in quality parts to keep your 991 running smoothly.