Evap control systems are often times difficult to diagnose. Try using information here: http://www.gearchatter.com/viewpost17788.php If that is more than you want to deal with you may want to take it to a good mechanic.
Isuzu uses the spark plug as a sensor of the burn efficiency inside the cylinder of the engine. Use of the wrong brand plug can cause this misfire code in a good running engine. Otherwise perform tune up to repair misfire
You have a problem. see a mechanic to read the computer codes. You need a code reader to determine what is malfunctioning, and after repair, to clear the code. If the problem is fixed, it still needs to be cleared. Pepboys sells a code reader from 80 - 200 bucks.
35560
Loss of compression is caused by bad internal engine wear or internal engine failure. Both mean the engine will need serious repair
Code 173 indicates the oxygen sensor is telling the computer that the engine is running rich.