2000 Maxima vibration/engine hum at 1500rpm

[amuley]

I have a 2000 maxima, whose Service Engine Soon light came on recently. After I took it to the dealer they said they had to reset the ECM. Since I got the car back I am noticing a vibration/hum of the engine at ~1500rpm as I go higher things seem back to normal.

This is the second time my CEL has come on. The last time the dealer changed the injection coils at 36.5k and now I have 50k on the car.

Any ideas what could be happening ?
Thanks,
Aalok

[tdaily]

Is your car still under warranty?

[amuley]

Its close to 4years since I bought the car and I have less than 60k miles. Hope the problem is under warranty. I am taking it to the dealer tomorrow, will find out.