▁exhaust ive ▁review ▁of ▁alleg ations ▁of ▁un int ended ▁acceleration ▁on ▁Toy ota ▁and ▁Lex us ▁vehicles ▁and ▁six ▁times ▁the ▁ag ency ▁closed ▁the ▁investigation ▁without ▁finding ▁any ▁electronic ▁engine ▁control ▁system ▁mal function ▁to ▁be ▁the ▁cause ▁of ▁un int ended ▁acceleration . ▁ ▁In ▁ 2 0 0 4 , ▁the ▁N HT SA ▁launched ▁a ▁pro be ▁of ▁thro tt le ▁control ▁systems ▁on ▁around ▁ 1 ▁million ▁Lex us ▁and ▁Toy ota ▁sed ans . ▁ ▁Upon ▁that ▁pro be , ▁Toy ota ▁ur ged ▁the ▁N HT SA ▁to ▁define ▁the ▁issues ▁as ▁quick ▁burst s ▁where ▁the ▁engine ▁sur ged ▁to ▁" something ▁less ▁than ▁a ▁wide - open ▁thro tt le ." ▁The ▁company ▁compared ▁the ▁compla ints ▁to ▁previous ▁sudden ▁un int ended ▁acceleration ▁cases ▁the ▁N HT SA ▁de emed ▁" driver ▁error ." ▁ ▁It ▁also ▁said ▁the ▁computer ▁could ▁not ▁open ▁the ▁thro tt le ▁without ▁the ▁acceler ator ▁ped al ▁pressed , ▁and , ▁the ▁bra kes ▁would ▁be ▁able ▁to ▁stop ▁the ▁car ▁anyway . ▁ ▁After ▁several ▁months ▁of ▁investig ating , ▁the ▁N HT SA ▁said ▁it ▁found ▁no ▁evidence ▁of ▁a ▁defect ▁and ▁there ▁was ▁no ▁data ▁indicating ▁any ▁bad ▁parts . ▁Christopher ▁Sant ucci , ▁an ▁employee ▁of ▁Toy ota ' s ▁Washington , ▁D . C . ▁office ▁and ▁an ▁N HT SA ▁employee ▁until ▁he ▁was ▁h ired ▁by ▁Toy ota ▁in ▁ 2 0 0 3 , ▁test ified ▁that ▁he