I have an '02 Maxima GLE with 144k miles on it, bought ~2500 miles ago. I'm experiencing a slightly rough idle when my car is in gear and also a slightly high idle speed (900-1050 rpm). While I'm stopped in gear, the engine will sputter like it's about to stall, but doesn't. This only happens when in gear and tends to get worse as the engine and transmission heat up. Also, the engine sometimes sputter when put under a medium to heavy load (i.e. accelerating to enter onto a highway) at around 2.5k rpm. One time, the car stalled while stopped and gave an error code for the crankshaft sensor. I replaced that sensor, both camshaft sensors, and cleaned the throttle body. After that, I performed the idling relearning procedure. The engine stopped stalling after that work was done, but it is still sputtering. The MAF sensor is brand new, replaced because it failed not long ago. What should be the next thing I check/replace, the sputtering is quite annoying.

 

Did you install Hitachi sensors all-the-way around? These engines are very particular about their electronics.

Your high idle means the relearn didn't stick. Many people have needed to replace the TB after a cleaning since the car acts like an a$$ and rejects the relearn. Sucks, I know.

 

Not Hitachi, but I didn't cheap out on them either. Even after the relearn procedure, the rpm only goes down to 850 as reported by my OBDII reader. This issue was present before cleaning and that was the simplest first step towards a fix and hasn't changed for better or worse after it was cleaned...