I have a 1996 ES 300 and the check engine light is on after having egr valve cleaned and suction valve replaced and also transmission speed sensor replaced---diagnostic codes indicated these areas.
While driving speeds 40 mph and 60 mph, rpm will move from erratically from
3 to 4 and then settle back down---the car sound is different for this hiccup
and then it runs fine....is this a transmission problem--gear shift???