1992 Honda Prelude SI, 160,000 miles

I will try to make this short but I want to give you alot of details to consider. Last week my car was missing really bad, so i got a tuneup and everything was fine for a day. The next day I was at a traffic light and my car just cut out, no sputtering or anything. Anyways that happened a few times, it would also take a couple minutes of cranking to start back up. Then yesterday it cut off while I was driving, it started back off after 15 mins of cranking it. Last night on the way home it did it again and it wont start back up now, just cranks and cranks. I had to get it towed home. What could this possibly be, I just got a full tuneup, i can hear my fuel pump turn on when i turn the key on so that isnt it. My mechanic thinks I have I spark problem cause he pulled the wire and there was no spark at the bottom. I have a valve cover gasket leak and he said the oil could be dripping back on the crank sensor and messing with the crank sensor. make sense? He def thinks its electrical but Im just looking for some help cause I dont have the money to dump and dump trying to pinpoint the problem. Also, my check engine light isnt on, if i take it to Honda will they be able to hook it up to a computer and tell me the problem?? What do you guys think? Any help would be greatly appreciated.