First my blazer started running hot an the 4x4 started engaging on its own then I was losing antifreeze out of the radiator and reservoir so I thought water pump was bad then I noticed something leaking from my intake so now I'm thinking intake gaskets but I ran it out of gas and when I put more gas in it and started home it started missing so bad I barely got it home now when I start it it idles rough and misses and when I drop it down in drive it falls on its face but doesn't die. I know the vacuum lines coming off the transfer case are bad if I replace them will that fix all my problems?

 

This sounds like you have more than a vacuum line problem.

I have the 4-button type transfer case with the auto-4wd option on my Blazer (a 99) so my vacuum line configuration is a bit different. For a 3-button transfer case (2hi, 4hi, 4lo) the vacuum lines to the transfer case go to a mechanical switch that blocks or allows vacuum to be directed to the front axle engagement diaphragm depending on if the transfer case is in 2wd or 4wd mode. One line is vacuum supply, the second line goes to the diaphragm, and the third goes to a vent. So if the vacuum lines to the transfer are bad, there will be no vacuum to the front axle engagement diaphragm even if the the transfer case is directing torque/power to the front diff. This is how you lose 4wd due to a vacuum leak.

You didn't say what year your Blazer was. In the latter half of the 90s the 4.3Ls were known to have lower intake manifold (LIM) gaskets that could fail and dump coolant into the lifter valley causing extreme wear on the rod and crank bearings by oil contamination. I recall a forum member reporting that because he was using synthetic oil that when he got a leak, he was able to avoid this damage.

You should check your engine oil before starting it again and see if it is contaminated with coolant before you start the engine again.

As for what to do with the vacuum lines, if you are in a jam, you could block the vacuum supply line off the engine that should be located on top of the upper intake plenum. Doing so will stop the supply of vacuum to engage the front axle but also block the supply of vacuum to control your HVAC system. You could also try to block off the hose the supplies vacuum to just the transfer case to preserve your HVAC operation. But these hoses are known to leak too. This could help with the engine dying. I have heard of severe versions of these engines dying because of a connection between the air intake and one of the valve cover vents being disconnected. So you might look at that.

Here are links to pages that describe the vacuum hose layout for the 2nd gen Blazers with the 3 and 4 button transfer cases. The first gen set up is like the 3-button one.

https://blazerforum.com/forum/articl...po-np8-107011/
https://blazerforum.com/forum/articl...po-np1-107596/

 

Thank you. It's a 2000 Blazer LS

 

I also have checked for coolant in the oil and there is none. So I'm in the process right now of changing all 3 of the vacuum lines coming off the transfer case and see if or what it helps.