Information from:http://www.know-car.com/index.php/how-to-block-a-nissan-intake-hose
The intake hose in your Nissan is an essential part of the engine system. The intake hose connects the intake air filter to the engine and allows cool, clean air to be sucked into the engine. You may want to block the intake hose to troubleshoot other parts of the engine when you can't find the problem. Blocking the intake hose is generally easy as long as you have an efficient clogging item to use.
Step 1
Locate the air intake assembly on the right side of the engine bay.
Step 2
Disconnect the mass air flow sensor electrical connection by pressing in the release and pulling it out of the connector.
Step 3
Unhook the wiring harness clips from the top of the air box; they will flip up.
Step 4
Remove the three bolts that hold the engine cover on using a 5 mm Allen key. Remove the engine cover.
Step 5
Remove the air inlet assembly by unscrewing the two bolts with the screwdriver.
Step 6
Release the crank case vent hose spring clamp using the pliers.
Step 7
Expose the intake tube by disconnecting the crank case vent hose.
Step 8
Insert a cork into the intake hose. The snugger the fit, the better the intake hose will be blocked.
Step 9
Reconnect the intake hose onto the crank case vent hose and secure the spring clamp.
Step 10
Bolt on the air inlet assembly and reinstall the engine cover. Secure the wiring harness clips and reconnect the mass air flow sensor electrical connection.