GM-GMC: 1989 GMC Jimmy has been sabatoged, help, vacuum hose, vacuum line

Question
Someone went under the hood of my 1989 GMC Jimmy, I don't believe he had any tools. I do know he removed the air filter and a vacuum hose. The air filter has not been replaced as of yet, but the vacuum hose was (see below note concerning the hose). Now it shakes or shimmies when excellerating and I do not have full control of the excelleration.  Meaning it will not drive very fast no matter how much I excellerate. I was putting it in neutral so that it wouldn't stall on me as a safe guard. It didn't stall but the idle changed when I stopped excellerating. I had hard brakes, not power brakes after he got under the hood.  I found a disconnected vacuum hose, replugged it in and the brakes work fine now.  What could be causing the shaking and excelleration problem? Also my gas gauge does not register the correct amount of gas. No matter how much gas I put in, the needle goes to the 1/2 full mark and after a short period of driving it disappears below the empty mark or bobs between empty and 1/2 a tank. Please offer any advise you can think of.  Thank you so much for your help in these two matters.

Answer
There is likely still a vacuum line unplugged or misrouted.  This cannot be diagnosed over the Internet because there is no way to know what was disconnected or changed.

The fuel tank problem is likely either the sender/float or the gauge.  The sender is in the fuel tank and the tank will have to be removed to gain access to it.  GM fuel gauges tend to bounce around, but they will usually indicate when the fuel supply is about to run out.