"strangle to death," c. 1400, probably from Middle English throte "throat" (see throat) + -le, perhaps a frequentative suffix (as in spark/sparkle), or a utensil suffix (as in handle), or simply to distinguish it from throat (v.), which in late 14c. was used to mean "cut the throat of, kill by cutting the throat." Related: Throttled; throttling.
1540s, "throat;" it appears to be an independent formation from throat, perhaps a diminutive form, not derived directly from the verb. The mechanical sense is first recorded 1872, short for throttle-valve (1824). Full-throttle (allowing maximum speed) is from 1848 in reference to steam engines.