Will an engine from a 99 jimmy work in a 96 jimmy?

Yes, an engine from a 1999 GMC Jimmy can work in a 1996 GMC Jimmy, but compatibility depends on the specific engine type and any modifications needed for wiring and sensors. Both models are part of the same generation, so they share many components, but it's essential to verify that the engine mounts, transmission compatibility, and electronics are aligned. Always consult a professional or reference specific repair manuals for detailed guidance on the swap.