Ignition delay times for stoichiometric syngas mixture with large excess of CO2 were measured behind reflected shcok waves in the following range temperatures of 974-,1106K, pressure of 101-2.6 atm, and a syngas/air mixture of H-2 = 8.91% mechanisms show that will validated mechanisms are able to capture the trends in data. Sensitivity analyses indiacte the importance of the chain branching. H + O-2 = O + OH (RI) reaction along with the termination H + O-2 + CO2 (R2) reaction for the entire experimental range. Measurement of K-2 was the carried out near 1300k and 8 atm in separate experiments using widely used GRI-Mech V3.0 natural gas mechanism.Hence we are recommend the low pressure limiting expression provided by GRI-Mech v3.0 mechanism, k(0()Co2) =4.2 x 10(18) x T[K](-.86) (cm(6/)mol(2/)s) for use with kinetic modeling for the range T = 800-1305 K and p= 1-8 atm. To the best of our knowledge, we present the first ignition delay times for H-2/CO mixtures with CO2 addition and the first high-temperature(T > 900k) determination of K-2