One problem related to accelerator pedal has been reported for the 2007 Toyota Yaris. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2007 Toyota Yaris based on all problems reported for the 2007 Yaris.
Accelerator on 2007 Yaris is sensitive at lower rpms making it difficult to start off in first gear causing a potential safety issue when starting off on a hill or steep grade. Was told by both the dealership and Toyota that there is nothing they can do, it's a design issue. The dealer did mention that they had received other complaints regarding the sensitivity of the accelerator. I've owned manual transmissions my entire life and although you expect differences in accelerator and clutch combinations, this is the worst I've ever owned.