Holley Sniper EFI replacement oxygen sensor on a white background
A close-up of a Holley Terminator X Bosch wideband O2 sensor, shown against a plain white background.
Close-up of a Holley EFI 554-155 oxygen sensor on a white background
A black Bosch LSU wideband oxygen sensor replacement with a multi-pin connector on one end and a smaller plug on the other, shown against a plain white background.
Black Holley wideband lambda sensor with cable on a white background
Holley Sniper EFI replacement oxygen sensor on a white background
A close-up of a Holley Terminator X Bosch wideband O2 sensor, shown against a plain white background.
Close-up of a Holley EFI 554-155 oxygen sensor on a white background
A black Bosch LSU wideband oxygen sensor replacement with a multi-pin connector on one end and a smaller plug on the other, shown against a plain white background.
Black Holley wideband lambda sensor with cable on a white background

Holley EFI Oxygen Sensor – Sniper EFI & Terminator X Replacement

554-155

$152.95
/
Shipping calculated at checkout.

The Holley EFI Bosch Wideband Oxygen Sensor is a genuine replacement sensor designed for Holley Sniper EFI and Terminator X EFI systems. This wideband lambda sensor delivers accurate air/fuel ratio feedback to the ECU for precise fuel control, self-learning operation, and engine tuning.

Featuring an M18 x 1.5 screw-in thread and factory-applied anti-seize compound, this replacement sensor installs quickly while providing the reliability expected from Bosch OEM technology. Whether replacing a worn sensor or keeping a spare in the trailer, this service part helps maintain accurate fueling and optimal EFI performance.

Includes:

  • (1) Bosch Wideband Oxygen Sensor
  • Pre-Applied Anti-Seize on Sensor Threads
Specifications
Specification Details
Manufacturer Holley EFI / Bosch
Part Number 554-155
Product Type Wideband Oxygen Sensor
Sensor Type Wideband Lambda
Band Type Wideband
Thread Size M18 x 1.5
Mounting Style Screw-In
Connector Gender Female
Fit Type Universal
Thread Preparation Anti-Seize Pre-Applied
Fitment
EFI System Compatibility
Holley Sniper EFI Compatible
Holley Terminator X Compatible

Fitment Notes

  • Direct replacement oxygen sensor for compatible Holley Sniper EFI systems.
  • Direct replacement oxygen sensor for compatible Holley Terminator X systems.
  • Uses an M18 x 1.5 oxygen sensor bung.
  • Universal screw-in design.
  • Verify connector style and ECU compatibility before ordering.
Tech Insight

1. Why is a wideband oxygen sensor important?

A wideband oxygen sensor continuously measures the engine's air/fuel ratio and provides feedback to the ECU for fuel corrections, self-learning, and accurate tuning.

2. When should the sensor be replaced?

Replacement is recommended if the sensor becomes contaminated, damaged, slow to respond, or no longer provides accurate air/fuel ratio readings. Keeping a spare sensor is common for race and off-road vehicles.

3. Does the sensor come ready to install?

Yes. The threads feature factory-applied anti-seize compound to help simplify installation and future removal.

4. What thread size does it use?

This sensor uses the industry-standard M18 x 1.5 oxygen sensor thread and installs into a compatible welded sensor bung.

5. Is this an original Bosch sensor?

Yes. This replacement uses a genuine Bosch wideband oxygen sensor specified for compatible Holley Sniper EFI and Terminator X systems.

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