my 1997 blazer 4x4x isnt working . installed new transfer case switch no help.i have vacuum at the switch but no vacuum at the actuator. also has a little miss. i sprayed all around the intake manifold with no rev up at all. any advice would help . when in nuetral the front drive shaft turns. when in 4 hi drive shaft doesnot turn so i think the motor is working just no vacuum at the transfer case switch or at the actuator/?

 

Have you physically checked the vacuum lines under the hood? Depending on where you did your test spraying of I'm assuming was carb-cleaner or starter-fluid, you might have missed the leak. The hoses for the vacuum on our Blazers tend to rot starting at about 15 years old.

If you also have issues with the HVAC system not directing the air flow to where you expect or where the air is directed changing when the engine is under load, that is an indication that you have a vacuum leak since the system that supplies vacuum to the transfer case and front axle also supplies vacuum to the HVAC air control actuators.