have 3800 SC engine-throughs code p0455 emission evap large leak

What is your question?

symptoms- brake pedal shutters and pulses-also engine temperature gauge doesnt work falls to zero. seems to only happen when engine hot or good and warm. live in cold climate in canada when leave cool down and start symptoms are gone- problem is intermitent symptoms always seem to be together. wondering if EGR could be the problem? not sure how the vaccuum can effect the the temperature gauge or the sending unit?