I replaced gas cap and PCV valve and still get p0442 small leak code.I was trying to replace all vacuum hoses as they look almost worn out and I couldn't find replacement online anywhere. Does anyone know the OD/ID for these vacuum hoses? Also I notice a hiss sound from right side of the engine when I turn off vehicle. Any suggestions>?

 

It is always good to provide as much info regarding year, model etc. because they are all different. Anyway, there should be a vacuum reservoir in that area and depending in the year,some were more prone to develop leaks than others. you might start there

 

2000 FORD E-250 V8 5.4L Gas