On a 2003 S10 with a 2.2L engine, the ignition coil is typically located
on top of the engine, near the distributor (if equipped) or directly on the spark plug tubes. It's a fairly compact unit and may be difficult to immediately spot unless you know what you're looking for. It's usually a black rectangular or cylindrical component with several wires connected to it.
Because its location can vary slightly depending on specific model and trim, I strongly recommend looking up a picture of the engine bay for a 2003 Chevy S10 2.2L online. A quick image search of "2003 Chevy S10 2.2L engine bay" will show you exactly where it is on a similar vehicle. This is far more reliable than a general description.
