99 Es300 Sputtering Problem

[hern]

Today, I got my new brakes on the front had to replace the rotors and pads costing me $140 for the front brakes. Sad. Anyways, now that it is cold and winter almost my car has been doing wierd sputtering. I'll start the car and it will sputter like the exhast goes on and off type thing. It does it its worst when it is in reverse and then goes away shortly after...it wil ldo it sometimes when im in drive but stopped but after the first 5min of driving it all goes away. It also sometimes never occurs. Does anyone know why it could be sputtering? I could my transmission changed 5k miles ago and i got my oil changed yesterday. Does anyone have any ideas?

[SKperformance]

iacv