Can you adjust the lean on the car

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your Lucerne. If your OBD reader shows a "too lean" code even after replacing ignition components and checking for intake leaks, this may be due to an issue with fuel delivery or airflow metering. A faulty MAF sensor or O2 sensor can sometimes cause lean codes, as they control fuel adjustments based on air intake and exhaust gases. A weak fuel pump, clogged fuel filter, or dirty injectors might also restrict fuel flow, leading to lean conditions. Since it runs well at higher speeds but misses at idle, this may indicate a vacuum leak in the intake system. A scan tool that reads fuel trims in real time may help pinpoint the cause. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!