The impulse manifold is part of a starships impulse engine.

In 2375, during the final battle of the Dominion War, the USS Defiant scored direct hits on eleven Breen battle cruisers, although only three sustained severe damage. Odo later noticed that the three ships that Worf was able to damage more had been struck in their aft impulse manifold. Benjamin Sisko had the Defiant attack another Breen ship to test the theory and the Breen ship was successfully destroyed using the tactic. Captain Sisko soon had Ezri Dax inform the other Allied starships of their discovery. (DS9 novelization: What You Leave Behind)