The firing order for a 1987 Isuzu Pup with a 2.3-liter engine is 1-3-4-2. This means that the spark plugs fire in the following order:
1. Cylinder 1
2. Cylinder 3
3. Cylinder 4
4. Cylinder 2
The firing order is essential for the proper operation of the engine. If the firing order is incorrect, the engine will not run properly and may even damage itself.
