New replacement narrowband oxygen sensor for 1986–1987 Turbo Buick 3.8L engines equipped with the factory ECM and wiring harness. Critical for accurate fuel control in closed-loop operation, idle quality, cruise air-fuel correction, and overall drivability.
🔵 Blue Dot – New / Never Installed
Specifications: • Application: Narrowband O2 Oxygen Sensor • Fitment: 1986–1987 Buick Grand National / GNX / Turbo T / T-Type • Connector Style: 0258007057 4-pin OEM-style plug • Wiring: Pre-wired pigtail with insulation and retaining clips • Function: Monitors exhaust oxygen level to maintain proper AFR • Thread Size: Standard Turbo Buick exhaust bung • Condition: New — protective cap still installed
Condition Notes: • New — never exposed to exhaust heat • Clean terminals, tight connector lock tab • No corrosion or discoloration • Wrapped harness and clips intact
Why You Want It: A weak, contaminated, or slow-responding O2 sensor can cause rich/lean fluctuations, poor fuel mileage, bogging, hesitation, or tuning issues. Replacing it restores accurate closed-loop response and keeps drivability clean — especially beneficial before dyno tuning, chip upgrades, or performance modifications.
⚠️ All Turbo 6 Parts are sold as-is with no returns, refunds, or exchanges. Buyer is responsible for verifying compatibility before purchase.
