95 skylark won't start

Okay two weeks ago the car ran fine, cleaned it up put it in the bargain news....no problems at all. For the hell of it I gunked the engine. Car started sputtering and running rough, I let it get good and hot shut it down. Started it back up it was running a little rough, backed it into the garage and let it sit for a few days without starting it. Decided to start it in case someone called to see the car, it started right up but the check engine light came on and it still ran a little rough, I just assumed something was wet. I let it stand for a week and tried to start it today kept turning over but would not start, I pulled the plugs and put a set of new ones in tried starting it again, turns over but wont start, never had this problem in 5 years all of a sudden I go to sell it and gunk the engine now I have problems any Ideas......

id say something got wet and is either still wet or it shorted out because it got wet electrical problems can be time consuming and expensive to diagnose