▁compla ints ▁of ▁un int ended ▁acceleration ▁with ▁vehicles ▁from ▁both ▁those ▁br ands ▁rose ▁sharp ly . ▁Elect romagnet ic ▁inter ference ▁with ▁the ▁electronic ▁thro tt le ▁control ▁system ▁is ▁another ▁possible ▁cause ▁of ▁un int ended ▁acceleration . ▁Some ▁spec ulated ▁that ▁cos mic ▁ray s , ▁or ▁radiation ▁from ▁outer ▁space , ▁was ▁a ▁possible ▁source ▁for ▁alleg ed ▁electronic ▁mal functions . ▁ ▁The ▁Wall ▁Street ▁Journal ▁obtained ▁a ▁copy ▁of ▁a ▁pre lim inary ▁study ▁dated ▁on ▁February ▁ 4 , ▁ 2 0 1 0 ▁by ▁the ▁California - based ▁engineering ▁research ▁firm ▁Ex ponent . ▁ ▁The ▁initial ▁study ▁commission ed ▁by ▁Toy ota ▁beginning ▁in ▁December ▁ 2 0 0 9 ▁concluded ▁" Ex ponent ▁has ▁so ▁far ▁been ▁unable ▁to ▁indu ce , ▁through ▁elect rical ▁dist urban ces ▁to ▁the ▁system , ▁either ▁un int ended ▁acceleration ▁or ▁behavior ▁that ▁might ▁be ▁a ▁prec ursor ▁to ▁such ▁an ▁event , ▁despite ▁concert ed ▁efforts ▁toward ▁this ▁goal ." ▁ ▁For ▁the ▁study ▁Ex ponent ▁purchased ▁six ▁Toy ota ▁and ▁Lex us ▁vehicles ▁which ▁were ▁analyz ed ▁by ▁" engine ers ▁and ▁techn icians ▁special izing ▁in ▁mechanical , ▁elect rical , ▁and ▁autom ot ive ▁engineering ." ▁ ▁According ▁to ▁Ex ponent , ▁Toy ota ▁" did n ' t ▁limit ▁the ▁scope ▁or ▁budget ▁of ▁its ▁investigation " ▁which ▁is ▁being ▁shared ▁with ▁Toy ota ▁and ▁law m akers . ▁ ▁The ▁study ▁will ▁continue ▁for ▁several ▁more ▁months . ▁According