Chevrolet Repair: Blue smoke from exhaust, vacuum leaks, air control valve

Question
I have a 1993 Chevy Suburban 1500 2 wheel drive truck. I recently began having blue smoke come from the tailpipe. I have changed the valve cover gaskets, plugs (One of which had large oil deposits),wires and had a compression checked performed. After the mechanic tune up the truck he suggested that the motor was shot. I also had a trans issue and yesterday had the trans completely rebuilt. Their codes suggested a map sensor and IAC problem. Can this be a simple repair or is it likely that the motor is shot.

I am a little leary of the mechanic needless to say.

Answer
Well, the MAP sensor and the IAC are pretty easy.
The MAP sensor may be correct. it is actually a vacuum sensor. MAP=Manifold Absolute Pressure, or Vacuum. If there is a vacuum leak, the MAP sensor will store a code. Look for vacuum leaks.

IAC=Idle Air Control valve. That is a little electric valve in the throttle body that opens to allow air to pass the throttle plate during idling. it is extremely cleanable. A can of spray carb/PCV valve cleaner, and you can usually do it without even removing it.

The blue smoke could be from a cylinder not burning all its fuel. Could also be from dirty injectors allowing too much fuel. Run some injector cleaner thru a couple tanks of gas. Double the dose given on the bottle.

I am curious about the compression test. Was there a big difference in the numbers, or were they pretty close to the same?
A vacuum leak, like a stuck EGR valve, can make a good engine seem shot.
So check the vacuum with a vacuum guage.

Van