My car has an O2 sensor code on, MAF code as well as service engine warning. I had the sensor fixed. Also, I had the emissions tested along with the replacement of serpentine belts. The check suspension light is on occasionally. The car is very loud usually while idling. After all the checkups, the O2 sensor code is still on, the check engine light is on as well as the MAF code. Please advise me what to do next.
Hello, it sounds like you have quite a few things going on. I am going to do my best to break them down for you.
First if the engine is very loud when idling and the belt has already been replaced, there may be an issue with the tensioner or idler pulley.
Next, the Navigator is known for needing service to the air suspension system as it gets up in miles, the most common causes of these are the air struts themselves have failed, or one of the air lines has a leak.
Lastly, if the O2 sensor and MAF are continually coming back after the sensors have been replaced, the most common cause would be either an exhaust leak or a vacuum leak.
Qualified technicians such as the ones at YourMechanic will be able to diagnose these issues and recommend the best path to repair, starting with a diagnosis of your warning lights.