The 1998 Pontiac Transport van used a few different engines. To accurately determine the firing order, you
must know which engine is in your specific van. The firing order will vary depending on whether it has a 3.0L V6 or a 3.8L V6.
You'll find the engine information on a sticker usually located under the hood, or in your owner's manual. Once you have the engine displacement (3.0L or 3.8L), you can search online for the specific firing order for that engine.
