Chevy S -10

I have a 1997 Chevy S-10 truck 4.3 L V-6 with 109,000 miles on it. It has always started and ran great, but the other day it just stopped while driving. I have spark, I have fuel. I used starting fluid, I also tested both spark at the cap and on an individual plug. I am stumped. I have also had 3 semi mechanics look at it. What could be keeping it from running? It doesnt even cough like it wants to run. I have since change the cap and rotor and the plugs. And still nothing. The fuel pump is humming when key it initially turned on, but the starting fluid should have eliminated this if it was a fuel problem. There is also good fuel pressure at the tap on the engine. Any suggestions? Its going to the dealership on monday if I cannot figure it out