With no disrespect intended, perhaps you need to amend your testing methods.
It is extremely simple to test the entire ignition system. Find a garage that has a diagnostic oscilloscope, and hook up the engine. A healthy ignition system has a set pattern on the 'scope. You can also measure the firing voltages at the plugs. If the pattern is wrong, there are books showing each possible pattern. We detected a bent cam in a distributor on a Chevy 6 in just this fashion, after a bunch of good mechanics gave up.
If the ignition system is normal, check the fuel system by temporarily adding an electric pump piped to a different source.
How much vacuum to you have at idle?
Jon.
