This happens only once in a while but more often than not lately:

When I come to a stop after driving my idle speed drops to about 500 instead of 650 rpms. The same thing happens sometimes when I shift to reverse.
The base idle is fine, I checked. I also cleaned the TB and drained and refilled the ATF (4.25 qts). No CEL codes.

Anyone have any ideas what else I should check?

('95 GXE, AT, 99k)

 

my idle speed in drive is 500~550. not sure if it should be as high as 650 or now.

 

Clean you IACV, do fuel filter/pcv valve... that combo with a TB cleaning really picked up my idle its way more steady now it dont drop down to 500's in drive anymore.

 

Unless your engine is dying or the electronics are dimming I would'nt worry about it. But it should level out and idle smooth after about 5 sec or so.