Had this listed for nearly a week no replies reposted when fixed it now loads of replies not jumping the gun just coudn't understand why no one could reply sooner to what i thought was an easy question to answer to anyone with a boost gauge and ok running car
I would have but I dont frequent this board that much..........
the repair consisted of replacing the dump valve (slight leak)
washed the air filter (precaution)
and 2 loose connections on the intake plenum (vac pipes)
All good things to find, but you should always have a vacuum at idle so make sure you still do...........
Also, the negative reading is measured in In.Hg (mercury) and not as psi as some people think, it'll say that on the gauge itself.