Any CEL? If you have it, pulling the code would help enormously.
Any other symptoms? Need as much info as possible to narrow it down. Does it do this more at stops, going uphill, downhill, around corners, when you start the A/C etc...
"If you don't love me at my diddliest, you don't deserve me at my doodliest." - User ktluvscricket of reddit
Some commong causes and fix:
-Dirty MAF sensor, easy to clean with electrical or MAF spray. Let it dry thoroughly before reinstalling.
-Dirty Air Filter, can pull it out and inspect in 30 seconds.
-Deposits on throttle body, remove intake tube and spray/wipe down with throttle body cleaner.'
-Deteriorated intake mainfold gasket. The older ones were poor quality, get a replacement from Toyota and replace. Easy to do but takes time/patience to remove all the bits and pieces.
I'd be very surprised if one of these weren't the cause.