I own a 2011 Nissan Altima 2.5SL. My car has about 84,000 miles on it. About two weeks ago while driving on the interstate going 70 MPH, the check engine light came on with a code, “P2423 HC Adsorption Catalyst Efficiency Below Threshold Bank 1″. After some research online the best possible scenario was the second Catalytic converter located under the vehicle was no longer doing its job. I thought this was odd since I already replaced it about 15,000 miles ago, but since it has a 5 year replacement warranty from Advance Auto Parts I took a chance and replaced it again. The vehicle ran through an entire drive cycle and passed all the readiness monitors. The issue is after a hard acceleration such as driving up a long incline going 40mph or greater the vehicle develops a rough idle at the next stop and clears up after driving on level again. I cleaned the throttle body and mass air flow sensor with no change. I did notice after cleaning the throttle body and MAF sensor the fuel trims are running closer to zero, long term around -5 and short term around -0 to -4. It was running a little leaner before completing these cleanings such as +5 to +9 on short term and +4 on long term. I cannot locate any vacuum leaks and I have driven close to 300 miles since with no codes. Also I replaced park plugs about 3 years ago. Any suggestion on what is causing this rough idle that almost feels like a miss fire after a long incline acceleration?
You must be logged in to reply to this topic.