dennys93na300z

Hello,
I recently bought a 93z n/a 5 speed from a friend. It's got 185,000. It had tons of normal repair work done already before he bought it. He did some things including new MAF, a few new injectors and new plugs. I added a 1 piece drive shaft (old one was toast), power steering pump, tie rod end, and a 2nd set of new plugs and 2 new coil packs. It's got a high rpm misfire that my friend was trying to fix when he replaced the MAF and the 2 injectors. Recently while driving at 60mph the car died. It then restarted when I pushed the clutch in. A few days later it died right after being started when I left for work, and would not start. Later that night I made sure the plugs were tight on the PTU (I've been reading these forums) and it re-started no problem. I didn't drive it, I ordered and installed a new PTU (old one in bad shape, and ALL plugs full of green corrosion). I cleaned everything with electronic contact cleaner, added permatex grease and turned the key. Car ran great. Still had a slight miss, but given the condition of the car and the connectors, I figured I need to clean them all. Drove it to work today no worries, tonight on the way home it died, restarted, then died again and needed towed to my mechanic. My Question? Besides the obvious checking the codes on the computer (never a check engine light) and checking for spark is there anything else I should look at? Fuel pump maybe? And according to the receipts, Nissan replaced the timing belt and water pump and tensioner at 165,000-but that was in 2006!!! Should I do it again? Any help would be appreciated.