Why does my Lexus have power surges between 1000 and 2000 rpm?

No.

could be the begining of a misfire that happens only under load. i think i would start by ck'ing for misfires

If I start to accelorate or back off on the acelorator between 1000 and 2000rpm the surges seem to stop. It is only at a steady cruise that the surges happen. Would that be consistant with the beginning of a misfire?

yes very possible

I will pursue that fix. Thank you.