Novel fuel blend made of diesel, waste plastic oil, propanol, and di-tert-butyl peroxide (liquid additive) is used in diesel engine thereby diminishing diesel consumption and improving performance and emission characteristics. In this study, diesel was blended with waste plastic oil, propanol, and di-tert-butyl peroxide as liquid additive at different proportions in order to improve its physio-chemical properties. Blend ratios of test fuels used in this work were 100% of Diesel, 80% of Diesel-20% of Waste plastic oil (DW), 70% of Diesel-20% of Waste plastic oil-10% of Propanol (DWP), 60% of Diesel-20% of Waste plastic oil-10% of Propanol-10% of di-tert-butyl peroxide (Additive) (DWPA). On comparing with diesel fuel, average brake specific fuel consumption and brake thermal efficiency of DWPA blend increased by 11.96% and 8.78% respectively, It was also shown that the average brake specific CO and HC emissions of DWPA blend increased by 3.87% and 15.7% respectively, however brake specific NOx and smoke emissions of DWPA blend reduced by 8.08% and 35.36% respectively due to addition of liquid additive as di-tert-butyl peroxide.