What cylinder is 4 on a 2002 LS 3.9 V8?

On a 2002 LS 3.9L V8 engine (likely a GM engine found in various vehicles like the Chevrolet Impala, Monte Carlo, etc.), cylinder numbering typically follows a standard GM pattern. However, there's no single universally agreed upon way to visualize the engine's orientation in relation to the vehicle.

To find out which cylinder is #4, you need to look at the engine itself. The cylinder numbers are usually cast directly onto the engine block or the valve covers. They will be sequential, and you'll see them from the front of the vehicle (radiator side).

* Look for markings: Check the engine block near the cylinder heads for cast numbers. They'll be near the spark plug wells or slightly below.

* Consult a repair manual: A repair manual specific to your vehicle's year and model will have a diagram clearly showing the cylinder arrangement. This is the most reliable method.

* Online resources: Searching online for "[your vehicle year, make, and model] engine diagram" might provide a diagram, but always double-check its accuracy against a reputable source like a repair manual.

Without a visual reference of your specific engine, it's impossible to definitively state which cylinder is #4.