1-8-4-3-6-5-7-2
This means the spark plugs fire in that order, starting with cylinder #1.
Here's a breakdown:
* Cylinder #1: Located at the front of the engine, passenger side
* Cylinder #8: Located at the rear of the engine, passenger side
* Cylinder #4: Located in the middle of the engine, passenger side
* Cylinder #3: Located at the front of the engine, driver's side
* Cylinder #6: Located at the rear of the engine, driver's side
* Cylinder #5: Located in the middle of the engine, driver's side
* Cylinder #7: Located at the front of the engine, passenger side
* Cylinder #2: Located at the rear of the engine, driver's side
Important Note: This firing order applies specifically to the 4.3L Vortec V6 engine. If your Astro van has a different engine, the firing order will be different.