One problem related to engine exhaust system has been reported for the 2007 Toyota Avalon. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2007 Toyota Avalon based on all problems reported for the 2007 Avalon.
Intermittently, upon heavy acceleration exhaust emits a hydrogen sulfide type (rotten egg) odor. Took to delivery dealer and tech could not duplicate &. Took car to another dealer. Both dealers acknowledged that Toyota was aware of problem. Both stated that Toyota had replaced/repaired exhaust or catalytic converters. However subsequent to 2003 models Toyota would no longer offer repair or solution for my 2007 model. Service tech suggested using higher grade gasoline. I have used mid and premium grade gas with no change in result.