There isn't one inside! All sensors and vis units are external and accessable. That is the only plastic component that fits the description. Correct me if I am wrong here guys but the only parts connected to the plenum are:
- Power vis unit-screwed in.
- Balance vis unit-screwed in.
- MAF sensor-screwed in.
- Purge valve-screwed in.
- Then throttle body with potentiometer and IAC valve screwed in place.
- Other than that its push fit breather piping.
As for pressure sensor, lost me there bud unless it is the MAF sensor? But that's external.