Intake manifolds were components on NX-class starships and shuttlepods.
In 2153, Commander Tucker advised against increasing speed in the thermobaric cloud perimeter of the Delphic Expanse, as the intake manifolds of Enterprise NX-01 were having trouble processing the gases. (ENT: "The Expanse")
The same year, the starboard thruster of Shuttlepod 2 was failing caused by debris in the intake manifold. Travis Mayweather was able to purge it. (ENT: "Impulse")
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 shuttle he was flying into the intake manifolds of a Xindi-Insectoid patrol 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 the comet Burke as cover to covertly approach Mars while sending a team to infiltrate John Frederick Paxton's relocated base. (ENT: "Terra Prime")