The study investigates the mechanical behaviour and microstructure of Metal Injection Moulding (MIM) parts made with Additive Manufacturing (AM) moulds for the automotive industry. With the trend towards speedy prototyping and production of personalized components, incorporating AM technologies such as Stereolithography (SLA) into mould-making can possibly make the MIM process more straightforward. The research employs SLA to 3D print high-temperature resin moulds, then bronze metal casting and sintering to produce MIM parts. Microstructural analysis mainly involved porosity analysis using Scanning Electron Microscopy (SEM), while mechanical properties were found through Brinell hardness testing. Mechanical properties such as hardness are quantified and compared with conventionally moulded counterparts. Experimental tests are used to maximize mould materials and sintering conditions, with particular reference to minimizing porosity and optimizing metallurgical integrity. Results show that AM moulds offer geometrical flexibility but need post-processing for the elimination of adhesion problems. Minimization of oxidation level was achieved through the addition of carbon powder during sintering optimized the mechanical performance. Even with difficulties in mould removal and thermal inhomogeneity, the research proves that AM-based moulds can make MIM parts of competitive quality when meticulously optimized. This work adds to the developing incorporation of AM in MIM processes, providing critical insight into hybrid manufacturing for high-performance automotive components. The future will see research into silicone moulds and improved finishing techniques to increase component quality and industrial scalability further.