Okay I have two problems with my blazer that I got first off when I click in my 4wd I can feel it kick in then it will slip in and out of it and gring or pop any ideas about what might be wrong?? And my second question/problem is when I start it up it seems to idle a little bit weird but still runs all that same until I go to pull out of the driveway it seems to sputter and jump I'll put the pedal to the floor and it will stay at 2 or 3 grand and just chug along then all of a sudden it will jump up to 5 grand and take off I'm not quite sure what's wrong I was told it could quitE possibly be a vacuum line after I replaced the plugs wires cap and rotor and fuel filter any suggestions to what might be my problem???