'93 Pathfinder XE

Brand new battery, she'll crank just fine but not catch. Same problem for weeks, normally I'd curse and wait a few minutes and it'd catch the next time I cranked it.

Couple weeks ago it just wouldn't catch, tried every 20 minutes for a couple of hours and again the next morning. Got it towed and had the distributor and spark plugs and cables replaced. Started up fine for a few days, then nothing.

Got it towed back to the shop, they couldn't get it started either. Checked to make sure it was getting gas and sparks, which it was. The mechanic went to lunch and when he came back it started right up. They upped the timing a little bit but otherwise said they couldn't figure out what was going on.

Started fine for the past few days, this morning...cranks and cranks but won't catch.

Any other suggestions? I like this shop and they seem competent so I'm probably getting it towed there again Monday AM. I could bring it to the dealer but figure they'd probably charge more and this other shop has already put several hours into it and know what's been done so far.