Fuel line flush on my 2011 Nissan Sentra
Asked by Shannon Mar 27, 2021 at 01:51 PM about the 2011 Nissan Sentra 2.0 S
Question type: Maintenance & Repair
I took my car into the dealership to replace the air flow sensor and to reset me
computer. They told me I needed a Fuel line flush. The next day I received the
code P0420 and now my car sounds like crap. Does this mean they ripped me
off and ruined my car, or do I really need a new Catalyic Converter? TIA
5 Answers
Buy a bottle of Techron for $15 for the fuel line flush. You may need a new converter or maybe just O2 sensors. I would check for air leaks in the intake system. They may have left a vacuum leak when they installed the sensor.
Thank you so much for your reply. I will suggest to my mechanic to check these out. Much appreciated!
Look for an exhaust leak ahead of the downstream oxygen sensor but after the catalytic converter. You said the vehicle sounds like crap now so I'm assuming it's louder than it was. If that's the case an exhaust leak will draw fresh air into the exhaust system, past the downstream oxygen sensor, and give you a false P0420 trouble code. Hope that helps! Jim
Thank you all and thank you Jim!! My mechanic ran a diagnostic 4 times and he came back with a downstream sensor as the problem. You were right! All is good now! I very much appreciate your comments!
Awesome! Thanks for letting us know! You're welcome! Glad to help!! Jim
