Can you put a 1996 jeep wrangler intake on 1990 Jeep Comanche engine?

No, a 1996 Jeep Wrangler intake manifold will not directly fit a 1990 Jeep Comanche engine. While both might use the same basic engine family (likely a 4.0L straight-six), there were significant changes in intake manifold design between those years. The bolt patterns, porting, and even the throttle body connection are likely different. You'd need to do significant modification, if it's even possible, and it's not a recommended project for someone without extensive fabrication and engine building skills. Sticking with a correct intake manifold for the 1990 Comanche is strongly advised.