Shock-tube ignition delay times for methy ethyl ketone (MEK; or 2-butanone) were measured at a reflected shock pressure of 1atm (+/-2%) in the temperature range of 1250-1850K at equivalence ratios of 0.5-2.0 for dilute mixtures in argon with fuel concentrations of 1.0%, 1.5%, and 2.0%. Rate constants for unimolecular fuel decomposition reactions were treated for falloff in pressure and temperature, with 9-parameter fits in the Troe formulism. A detailed chemical kinetic submechanism was developed and coupled to an existing C4 mechanism comprising 234 species and 1,369 reversible reactions. Model simulations show generally good agreement when compared to the available experimental data. MEK may be used as a fuel tracer, and thus further ignition delay time measurements were carried out by adding MEK to n-heptane in order to test the effect on ignition delay timing of blending these fuels together. It was found that autoignition characteristics of n-heptane remained unaffected by the presence of MEK fuel tracer.