Intake manifolds were components on NX-class starships.

In 2153, Commander Tucker advised against increasing speed in the thermobaric cloud perimeter of the Delphic Expanse, as the intake manifolds of the Enterprise NX-01 were having trouble processing the gasses. (ENT: "The Expanse")

Later that year, when Enterprise entered a polaric field in the Expanse, nucleonic particles flooded the intake manifolds and disabled the ship's propulsion systems. (ENT: "Similitude")

Still later in 2153, Captain Jonathan Archer released warp plasma from the cargo vessel he was flying into the intake manifolds of a Xindi-Insectoid ship, which overheated their engines. (ENT: "Stratagem")

In 2155, Commander Kelby ordered that the intake manifolds be modified to process cometary debris, as Enterprise would be using Comet Burke as cover to covertly approach Mars while sending a team to infiltrate John Frederick Paxton's secret base. (ENT: "Terra Prime")