hot starting- grinding away???

3 different shops cannot figure out why my 95 riv has so much trouble starting when engine is hot. If the car is cold or has been sitting for > 1 hour, then works like a charm. Otherwise, it will take 5 seconds to (finally) turn over. Car has 130,000 miles- but maintenanced well.
I'm not an expert, but could it be 1 of the many small vac/air hoses that has cracked over the past 10 years?
Unfortunately, I'm as clueless as the mechanics are.