have a 94 ls400 thats is giving me some wierd issuses. 1st of all the gas tank pressures it self alot ,when i remove the cap i blows atlot of air out, second car wont start most of the time like its not gettingany fuel. other times it will start and idle really low and no matter what u do ,floor it,give it aliitle gas ,anytthing it wont change from that slow idle.have to turn it off and restart. other times it starts just fine. the longer it sits more chance there is it wont start ... any clues?? please help