[Superman]

The vent theory is good. Further, I have had similar problems with other cars where rust and dirt were clogging CIS components. Sometimes the car runs fine for a while, but rust starts stacking up somewhere and eventually impedes suficient fuel flow. At rest, the rust settles down and the passages open again. Until flow and pressure cause the rust to stack up again.

So, if the vent theory does not pan out, replace the fuel filter and disconnect all the other CIS componets. Blow compressed air through those lines and rinse out the components. Check the screen in the tank. Reassemble.