Thanks for your suggestions, it's not the first time I've heard that a contaminated fuel supply system can cause long term issues! Fortunately, my tank looks brand new inside with no rust or varnish at all--looks like new. A previous owner has also installed a new primary pump as well as brand new accumulator and filter--I am certain that fuel reaching engine bay is clean as a whistle!

Buy anyways, a new discovery have been made! I
Unscrewed the the fuel distributor from the air mass
Meter body, and low and behold, found that everything worked as it should! With pump jumpered at relay plug, no fuel reached main four injectors! It seems that a previous owner had adjusted the mixture to be so rich (at the adjustment post) that even at rest position the plunger barrel at the fuel distributor was depressed to WOT position!

I did notice that I could hear the cold start injector spraying with the fuel pump hard wired on with engine off, should this be the case or is there a problem?

Thanks again!