Has spark has fuel, no start

Hey guys, I was hoping to get some advice. My car listed above is a 1991-1992 model year is only cranking but not starting. It had crapped out on me a few months ago while driving home from work. All of the accessories stayed powered, but the engine was off. I tried checking connections and disconnected the battery and then reconnected the battery hoping maybe it would reset something. No such luck, like every time it has stopped running on me it just cranked but not turn over. I had to get a tow back home and the advice from the tow truck driver said it sounded like the timing belt. So I went with that advice and had taken the cover off to expose the timing area. Inside looked great and discovered that the Nissan used a timing chain instead of a belt. I asked a family member to come take a look to make sure that the timing chain was good. He said he did not know much about timing chains/belts but since it is not loose and not broke that we wont mess with it and move on. He started checking the Nissan's connections and spark and said everything seemed fine and did not know what to call it. About to give up for the night, he tried starting the car in neutral and like there never was a problem to begin with the Nissan fired up. To make sure the issue did not exist still we turned the car off and started it a couple more times in park and it started just fine. He suggested that the Nissan's transmission was slipping and would need work later on. The Nissan ran solid for about a month and then shut off again the same way while on my way to work. This time putting the Nissan in Neutral did not work. I called the same family member and he said he could not get to the car until later. I left my wife the keys and had her drop me off at work. I checked back in with him about six hours later and he said the car started up fine and is possibly something in the fuel that is causing the car to fail, he suggested to replace the fuel filter since I was still using the original and that should be all that is needed. After replacing the fuel filter I continued to drive with no issues for about a couple of weeks and then the car died again while driving. We went ahead and replaced the fuel filter again along with the fuel pump. The Nissan has been hit an miss and each time I replaced a different spark or fuel problem that might help the issue. So far I have replaced the fuel filter, fuel pump, fuel relay, spark plugs, spark plug wires, rotor, distributor, cap, pick up coil, ignition coil, air filter, fuses, I am sure I have forgotten something that we replaced, but I have also used engine cleaner and cleaned out the distribution area and the spark plug area. At this point I have spark and I have fuel but the car just cranks with no start. I have noticed the spark plugs are wet with gas and oil when I pull them out to inspect them. I do not know if that means anything, but I have family that usually can diagnose and fix any car problems the family comes across and this one is going to need some outside help. If anyone has any suggestions that would be great. Thank you.