That is the million dollar question. Have I exhausted all electrical possibilities before I commit to removing the intake one more time, to install all new injectors w/o-rings and seals? I'm going to replace all fuel filters and do a more intense inspection of the coil and injector connectors, just to be thorough. But I'm asking if anyone can think of any other related sensor, valve, etc that might be a cause to this effect, that I have not thought of.