I had a family friend who had the same problem on their toyota sienna 2001, the car will continue to rev it self and will not change gear, the only way to get it to change was to release the throttle and then repress the throttle again, they ended up changing the transmission totally. Better do a proper check on your transmission components just saying also try scan the car.

Scan the car. If u do not have transmission issues, then u will have plug or coil issues or both. But scan the car.

@Banky3w would suggest you read this its almost similar to your case https://answers.yahoo.com/question/?qid=20090504084947AARfpnu

banky3w:
Please help my fellow nairalanders, my toyota camry 98 V6 started jerking when the engine reaches the uptimum temperature at first but now jerks constantly whether cold or hot. When moving, the engine revs higher suddenly before changing to the next gear even though i don't do that myself and whenever it tries to change gears when i'm 3000rpm and above, the gear shifts and then downshifts again contineously until i let up on the pedal a little. Please what is the probable cause and solution to this problem because i'm already spending much on this problem to no avail. Pls Help!

Only a scan will direct us in the right path.
You can contact Mayor or
08038221716 for scan.

Avoid replacing good parts.

banky3w:
Please help my fellow nairalanders, my toyota camry 98 V6 started jerking when the engine reaches the uptimum temperature at first but now jerks constantly whether cold or hot. When moving, the engine revs higher suddenly before changing to the next gear even though i don't do that myself and whenever it tries to change gears when i'm 3000rpm and above, the gear shifts and then downshifts again contineously until i let up on the pedal a little. Please what is the probable cause and solution to this problem because i'm already spending much on this problem to no avail. Pls Help!

let me give you a head start

the issue you are having seems to be transmission problem hence the shifts up and down as away to force transmission oil into right chambers for it to open a valve and able to engage into the next gear

but be fooled by touching anything on the engine your problem is a transmission one

here to understand the shifting of gears


https://www.youtube.com/watch?v=u4kM67f_P3A