Poor injector spray pattern is a much different problem than leaking ones. The throttle blipping that helps the problem makes me think that the idle air control valve may be suspect. The A/C helping the idle is another clue (I think the A/C being on opens the idle air valve a bit more than normal idle).

Before spending whatever criminal prices Bosch is charging for injectors these days, try cleaning the Idle Air Control Valve. Replacement might do the trick if cleaning doesn't.

Hope this helps.

Troy
1995 E420 93k