94 ford explorer XLT looses power

Hey guys.

I recently got a 94 explorer. The problem is that it has less power than a 4cyl. I’ve changed the plugs and wires. Changed the oil, and airfilter… there arn’t any vaccume leaks… and my plugs were a little loose going in and out… you know they had a little wiggle room. Any Ideas? Need any more info?

You need more info like compression and manifold vacuum readings. I am thinking exaust restriction.