It's possible. Disconnect your TPS (Throttle Position Sensor) and take a test drive to see if the problem is gone. If it's gone, then you have a bad TPS. The TPS is mounted to the side of your throttle body. Here's a thread that features the throttle body:
http://www.toyotavantech.com/forum/s...-Throttle-Body. 5th picture down is a straight on view of it. Near the bottom of the 1st post I have a video link that shows how to adjust it.
There is a little spring clip on the TPS wire connector that makes it difficult to remove. Use a dental pick or something similar to remove the clip, then the connector will pull right off. Tim