Where is the 1 cylinder 1988 Chevy Cheyenne?

There's no such thing as a 1-cylinder 1988 Chevy Cheyenne. The 1988 Chevy Cheyenne, like other full-size trucks of that era, came with V6 or V8 engines, not a single-cylinder engine. A single-cylinder engine wouldn't have the power necessary for a full-size truck.