Why my Prius suddenly drops its acceleration? on 2001 Toyota Prius

After driving sometime it suddenly drops its speed and I had to press the gas more to maintain the same speed. This is happening once in a while for the past one month. Toyota dealer inspected it and said he don't find any problem with the car.. but still the situation continues.

by in Pleasanton, CA on February 22, 2012
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2 answers 2 comments
ANSWER by , February 22, 2012
leave it with them so they can experience the issue. there is a problem with the hybrid drive that needs to be determined. Roy
COMMENT by , February 22, 2012
Thanks for the response Roy.... but they are telling they didn't see anything there ... even the mechanic test drove it.. he didn't felt anything there.. and I cant reproduce the same whenever I want... it just happens... not sure what to do...
COMMENT by , February 22, 2012
once again, you need to leave it there till the problem happens so the tech can get an idea of what is going on. it takes time to track down these types of issues. Roy
ANSWER by , February 22, 2012
When does it happen? How long have you been driving? Warm or cold out? Did you change fuel recently or just filled up? Has the vehicle been serviced?