Impulse manifold
The impulse manifold was a vital part of a starship's impulse drive system.

During its third week of observing Humanity in 1957, a Vulcan survey ship experienced a malfunction in its impulse manifold, necessitating an emergency landing on Earth. ()

The impulse manifolds on  required checking every two hours to ensure they would not clog. Should they get clogged, it would cause the impulse engines to overload. ()

On February 12, 2152,  claimed the impulse manifolds aboard the Enterprise required purging as an excuse for why he couldn't go with Captain Archer to visit the Torothan planet. In actuality, Tucker did not wish to go because he did not want to spend time in a desert. Archer ultimately convinced them to go, but Archer himself would use the required manifold purging as an excuse to return to Enterprise after learning Zobral and his men were considered terrorists. ()

Later that year, Trip Tucker detached a section of hull plating from Enterprise that a Romulan mine had clamped on to. Tucker noted that detaching this section of the hull would expose a good portion of the impulse manifold. ()

In August of 2152, Tucker was about to purge the impulse manifolds when Archer asked him to fix the captain's chair. ()

Xindi-Insectoid vessels have narrow impulse manifolds with minimal deflector shielding. In 2154, Enterprise was able to destroy a Xindi-Insectoid scout ship with one photonic torpedo strike to its impulse manifold. ()

Later that year, Enterprise was able to pass through a subspace corridor after reconfiguring their impulse manifolds to prevent the corridor from destabilizing, as it had done for the crew of an Enterprise from an alternate timeline. ()

In 2375, Seven of Nine attempted to shut down 's impulse engines by tapping into the impulse manifold from main engineering to prevent the ship from entering a wormhole. ()

That same year, readying the  for departure, Nog noted that the impulse manifold was purged and clear. ()

Also in 2375, when the  was traveling through the Briar Patch, William T. Riker ordered full impulse. Geordi La Forge replied that the manifold couldn't handle full impulse in the Patch. ()

See also 
Plasma manifold
  for a modern, automotive analogy

de:Impulsverteiler
Propulsion technology