Hi,
Hope you can help me with this.. 2000 maxima with 100,000 miles is stalling. Using my code reader, I am getting a 420 code "Catalytic system efficiency below threshold". Does this mean that the cat need to be replaced ? Thanks in advance for your help

 

hey,
I own a 97' maxima and about two years ago, i noticed that when i put it in reverse it would stall. i talked to alot of people but one of them said to replaced both oxygen sensors. i did and it i cleared the codes that were in the system. it did not stall after that.
I hope that helps.
-Billy

 

Thanks for the info..I cleared the code and it is not stalling now. I'll watch it for a while and see if the stalling comes back.