The 8th character tells what engine you have. There are five different 4.3L engines: Z=TBI, (Throttle Body Injection)
2 different W engines:
CMFI, (Central Multiport Fuel Injection)
CSFI, (Central Sequential Fuel Injection)
One X engine= MPI, (Multiport Injection)
And one marine engine

 

Can't find a pic, just take the air filter housing off, one wing nut holds it on, and the service port is visible.

 

this thing?

 

Bad link, no picture. Your engine should look like this, the big black round thing is the air filter housing, with a wing nut on top:

 

yeah i knew that was the air cleaner just not sure where the port to hook the tester up is located. sorry if im being difficult. i appreciate the help though

 

Remove the cover then remove the housing. You'll see the service port on the throttle body. The fitting looks like the valve stem on a tire, (where you put the air in).

 

wheres it at from here?

 

The link doesn't work. To post images you'll need a web based host to store your images on first. Then use the icon in the "quick reply" tool bar that says "insert image" then copy the address of the image in the box.

 

 

do you have an email that i can send em to?