Tunable diode laser absorption spectroscopy (TDLAS) has gained popularity in measuring temperature, pressure and concentration of the species in combustion research. A new methodology based on peak absorption was adopted by Sreenath et al. [1] for calculating step profile in temperature. Current work adopts the same methodology for CO and CO2 to measure the non-uniformity of temperature along with uniform concentration. The temperature variations considered are step variation and quadratic variation. Simulations show that the selected lines perform well in calculating the profiles, without and with (1%) noise. The concentrations were also captured within 10% accuracy.