When your 2023 Ford Bronco displays the P0305 code, the powertrain control module has detected repeated misfires in cylinder 5. The 2023 Bronco continues to offer the same two engine choices as at launch: the 2.3L EcoBoost four-cylinder and the 2.7L EcoBoost V6. P0305 is a valid code only if your Bronco has the V6 engine, as the four-cylinder lacks a cylinder 5.
2023 Bronco Engine Options
The 2.3L EcoBoost I-4 produces up to 300 horsepower on 93 octane fuel, while the 2.7L EcoBoost V6 delivers up to 330 horsepower. Check your vehicle documentation or door jamb sticker to confirm your engine. Only the V6 has cylinders numbered 5 and 6.
Cylinder 5 Location
On the 2.7L EcoBoost V6, cylinder 5 is positioned on the passenger side bank toward the rear of the engine. Access may require removing engine covers and air intake components typical of turbocharged engines.
Common Causes of P0305
Spark plug degradation can occur even on relatively new vehicles, particularly with turbocharged engines that generate higher cylinder pressures. Ignition coil failure at cylinder 5 can cause isolated misfires. The direct injection system makes these engines susceptible to carbon buildup on intake valves over time. Boost system leaks can affect air-fuel ratios inconsistently across cylinders.
Diagnostic Process
Verify your engine configuration first. For V6 models, access and inspect cylinder 5's spark plug. Test the ignition coil through resistance measurement and swap testing. Monitor live misfire data during a test drive. Check boost system integrity for any leaks that could affect performance.