map sensor feed pipe need help

[big wad]

a question for you 1jz guru,s.does the map sensor have to feed directly off the plenum caus i just checked mine and it is hooked up to a line that runs forward through a one way valve into the bottom of the throtlebody. i suspect this could be my problem. can you help . cheers bigwad

[Norbie]

MAP sensors should always be on a dedicated connection to the plenum (ie not sharing it with anything else) and there definitely shouldn't be any valves in there! Ideally the vacuum line should be as short as possible as well.