Present research examines the relative performance, combustion and emission properties of a 10% HCNG (hydrogen-enriched compressed natural gas) blend in Sequential Port Fuel Injection (SPFI) and Conventional Manifold Fuel Injection (CMFI) engines. The experiments were performed under the conditions of the Wide-Open Throttle (WOT) at the Maximum Brake Torque (MBT) spark timing with a range of engine speeds of 2000 to 4000 rpm. The same was done online by blending Hydrogen with CNG to provide a similar mixture preparation in both modes of injection. The findings show that SPFI has a great improvement in the efficiency of the engine and combustion performance over CMFI. A 15.87% improvement by CMFI was a 16.06% brake thermal efficiency of SPFI at 4000 rpm. There was an increase in volumetric efficiency of about 20% in SPFI mode and a decrease in brake-specific fuel consumption at all the speeds that were tested. It was found that the peak cylinder pressure (34.9 bar) of SPFI was higher than 27 bar in CMFI, which also shows enhanced homogeneity of the mixture and quicker flame spread. The accumulation of emission analysis revealed a significant decrease in CO (19.17) and HC (>50) emissions with SPFI, but the whole of NOx emission growth was attributed to the high in-cylinder temperature that comes with hydrogen enrichment. In general, SPFI exhibits high thermo-chemical efficiency and cleaner combustion properties in terms of using 10% of HCNG mixtures, which underlines its applicability in the field of sustainable use of alternative fuels.