The Silent Killer of Fuel Efficiency: How Lambda Sensor O2 Sensor Failures Cost Drivers $2.3B Yearly Your Engine's Secret Snitch: Lambda Sensor O2 Sensor 101 That little metal probe sticking out your exhaust pipe? That's your lambda sensor O2 sensor - the OG whistleblower of emissions control. These unsung heroes monitor air-fuel ratios 100x/sec, feeding…