2003 3.5 V6 Pathfinder, 140,00 miles: My gas mileage is dropping and I'd like to check the compression. Not only can I not find the plugs, I can't find any evidence of an ignition system at all! Is this all buried under the intake manifold? Any suggestions would be appreciated - John

The 3.5 motor uses a direct ignition system so there are no spark plug wires. Each cylinder has it's own ignition coil. If you take off the engine cover you can see where the spark plugs are.