Mitsubishi Repair: gen 2 eclipse, octane boost, coil pack

Question
hello, i have a 95 eclipse rs and am having a few problems with it. it has been sitting for almost 2 years before i acquired it. i drained all the bad gas out and put in premium with octane boost and techron. the car has an intermittent problem that i am assuming is electrical. usually i try to start it and it will sputter and run at an almost stall. most of the time it will just stall out like its not getting fuel. i checked everything from the pump to the injectors and it is getting plenty of fuel. other times it will have a slight rise in rpm's and it will sit there and jump a few hundred rpm's every few seconds and sometimes will start to run great. there is the harness  that goes from the computer under the hood to places such as the injectors and the coil pack, cam pos sensor and the crank pos sensor. not sure if it is a coincidence but i can shake that harness and it will make or break the cars running.  now right after the car will be running perfect, no popping, no smoke, no nothing just good running, i can shut the car off, and it will not start back up. what could it be?

Answer
Jonathan: Got an AutoZone close by? They will code your car for free and that would rule out any problem with the computer or weak sensors. You know don't you that Mitsubishi farmed out the building of their computers to another company which did not build very good ones. A piece will start to break down and so leak into the computer with time it will kill off the computer. One of the problems of the computer going is with the car not starting after running good and the rpm's. So you need to have that car coded, if not an AutoZone then Sears would sell a hand held meter, that you could check your car yourself or take it to another shop. All coding is, is that they hook their computer up to your car's computer; then their computer kicks out whatever is going on with your sensors or the computer. You need to buy yourself a repair manual for your car too, it would help to explain things to check and whatever your readings should be. The shuting the car off and it not starting again makes me think of a weak sensors or maybe a weak relay. Have you checked all the fuses and relays? When you open the hood of the car, standing looking at the engine. There should be a black box up on the driver's side of the car, over by the firewall. It's cover should explain what relays and fuses it has. Then again over by the battery and the firewall on the other side of the car, should be two more boxes. Again on their covers, that explains what is in the box. Might check those, oh if you do find a bad relay or one that does not look very good. If you decide to replace it, always remove the neg cable off the battery, replace with the new piece and then put the cable back on. If the car sat for 2 years well almost did you do a tune up on it? New stark plugs, wires, distributor cap and rotor? You could also have a vacuum leak too, that would cause problems with the idle. Should have the compression checked too, just to be on the safe side of things. I hope this helps and good luck! Linda