Mitsubishi Repair: fuel injectors, valve cover gasket, fuel injector cleaner

Question
1996 rs  i bought this for my son. Just spent 1100 on a new computer for it. now its running rough. I had all the wires plugs etc changed. I added fuel injector cleaner(or whatever that stuff was the auto store recommended)How do you change or fix the fuel injectors?
Alos I think the guy said the O ring was bad as there was oil in it when they took out the  #2 spark plug

Answer
Pat,
Most auto parts stores also sell a service manual for the 96 Eclipse.  Both Haynes and Chiltons make a service manual which will instruct you on replcing your fuel injectors.  It's relatively simple, but I don't go into specific replacement instructions because it would take too long, and it can be real dangerous when working around gasoline.

Oil in a spark plug well usually indicates a worn valve cover gasket.  There are 4 circular seals for the spark plugs (they kind of look like o-rings) and over time they will weaken and crack; which can allow oil to seep into the hole.  Excess oil will prevent the spark from firing.  It may be time to replace your valve cover gasket.  If only 3 of the 4 cylinders is firing, you'll get a terrible idle.
Good luck!