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Throttle body cleaning

Clean the Mazda MX-5 NB throttle body and throttle plate deposits to improve idle stability and throttle response, with sensor/solvent safety controls.

Difficulty
Intermediate
★★☆☆☆
Est. Time
45-90 min
Models
NB1 & NB2
Last Updated
2026-02-26

Before You Start / Safety

  • Work on a cool engine in a ventilated area.
  • Wear nitrile gloves and eye protection.
  • Use throttle-body/carb-intake cleaner only as directed by product label.
  • Keep ignition sources away from solvent vapors.

Warning: “This should be an outdoor place with good ventilation because the substances you shall use are volatile.” https://rxmechanic.com/how-to-clean-throttle-body/

High-risk quote: “Be careful not to let any parts in the throttle body spill.” https://rxmechanic.com/how-to-clean-throttle-body/

Required Tools

  • Screwdrivers / hose-clamp driver
  • Clean lint-free cloths
  • Soft brush (nylon)
  • Throttle body cleaner
  • Small inspection light

Required Parts / Fluids

  • Throttle-body cleaner (sensor-safe type preferred)
  • Optional replacement intake hose clamp(s) or gasket(s) if damaged during removal

Model-specific notes (NB1 vs NB2)

  • NB1/NB2 are cable-throttle cars (not later drive-by-wire logic), so cleaning workflow is generally straightforward.
  • Access and hose routing can vary with stock vs aftermarket intake plumbing.

Manual-reference quote: “The Manuals are in PDF format. You can use Adobe Reader to read or print them.” https://www.mellens.net/mazda/

Step-by-Step Procedure

1) Baseline check first

Confirm symptoms before cleaning (idle dip, unstable idle, off-idle hesitation). If there is a hard fault/CEL, diagnose that separately instead of assuming deposits are the only cause.

Community quote: “I’m having some idling issues … vibration and RPMs drop down and eventually find their correct idle.” https://forum.miata.net/vb/showthread.php?t=484366

2) Access the throttle body

Remove the intake duct between airbox/MAF side and throttle body so the throttle plate and bore are visible.

High-risk quote: “Locate the air intake tube and loosen the clamps and mounting bolts to remove it.” https://www.2carpros.com/articles/throttle-actuator-service

3) Inspect deposits and clean gradually

Open the throttle plate by hand (engine OFF) and clean front/rear bore edges and plate perimeter using light cleaner application on cloth/brush.

High-risk quote: “Clean the throttle actuator bore housing and butterfly both the front and rear sides…” https://www.2carpros.com/articles/throttle-actuator-service

4) Avoid over-wetting sensors and seals

Spray minimally, wipe repeatedly, and keep cleaner out of electrical connectors. Do not aggressively pry at the plate or shaft.

5) Reassemble intake plumbing

Refit intake ducting and clamps fully. Ensure no vacuum hose is left loose and no cloth/towel remains in the intake path.

6) Start and relearn idle behavior

Start engine, allow it to stabilize, then perform a short drive and re-check hot idle.

Community confirmation quote: “Lots of thick black gunk came out… It idles much more steady now, and my idle droop is GONE!” https://forum.miata.net/vb/showthread.php?t=1344

Torque Specs / Capacities

  • No single universal torque value is provided here because clamp and hardware styles vary by intake setup and market.
  • If you removed throttle-body fasteners, torque to your exact NB year/manual specification.

Verification / Post-service checks

  • Stable hot idle with less hunting/droop
  • No intake hiss/vacuum leak sound
  • No new warning lights after test drive
  • Throttle returns cleanly to idle without sticking

Uncertainty / Open Questions

  • Publicly extractable factory manual data in this environment did not yield one definitive NB torque table for all relevant intake/throttle hardware.
  • Community experience is consistent on symptom improvement, but improvement magnitude varies with root cause (vacuum leaks, IAC, ignition, fueling).

Images

No reusable images were added in this run.

Image Credits

  • No images used.

Sources

  1. Mellens.net — Mazda Miata Factory Service Manuals. Retrieved 2026-02-26. https://www.mellens.net/mazda/
  2. ScegliAuto — Mazda Mx 5 - Throttle body (tutorial index). Retrieved 2026-02-26. https://www.scegliauto.com/en/video/mazda/mx-5/corpo-farfallato/tutorial/
  3. 2CarPros — Throttle Actuator Service. Retrieved 2026-02-26. https://www.2carpros.com/articles/throttle-actuator-service
  4. RX Mechanic — How to Clean Throttle Body without Removing It? Retrieved 2026-02-26. https://rxmechanic.com/how-to-clean-throttle-body/
  5. Miata.net Forum — Throttle Body Cleaning - newbie (NB 1999-2005 section). Retrieved 2026-02-26. https://forum.miata.net/vb/showthread.php?t=484366
  6. Miata.net Forum — Clean your throttle body! (NA/NB Power Mods). Retrieved 2026-02-26. https://forum.miata.net/vb/showthread.php?t=1344