# Sienna has a burping problem

**URL:** <https://community.cartalk.com/t/sienna-has-a-burping-problem/42371>\
**Category:** Maintenance/Repairs\
**Tags:** sienna, transmissions, toyota, engines\
**Created:** [January 12, 2010, 6:30pm UTC](https://community.cartalk.com/t/sienna-has-a-burping-problem/42371 "2010-01-12T18:30:57Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![klimas0501](https://avatars.discourse-cdn.com/v4/letter/k/41988e/32.png) [@klimas0501](https://community.cartalk.com/u/klimas0501)\
**Post date:** [January 12, 2010, 6:30pm UTC](https://community.cartalk.com/t/sienna-has-a-burping-problem/42371/1 "2010-01-12T18:30:57Z")

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My 200 Sienna is doing something I call hesitating… only when cold and only when the car is under load, like going up a hill or accelerating onto an interstate. It sounds like the engine is disengaging or skipping or something. No codes appear.  
  
 These are the things I have had done: new timing belt, new spark plug wires, new MAF, and assorted tuneup stuff (plus new tires and battery (which don’t count, I think.  
  
 Problem started about a year ago with a huge backfiring episode. I have taken it in at least 5 times to two different mechanics, one a dealership. And the check engine light never comes on.  
  
 HELP!