Anonymous asked in Cars & TransportationCar MakesChevrolet · 6 months ago

I have a chevy 350 is it normal for it to miss when I unplug the vaccum advance?


even with the distributer fully advanced to the point of hitting the intake it still has a miss without vaccum advance hooked up a local mechanic shop says even with the vaccum advanced unhooked it shouldn't miss like that with the distributer fully advanced to the point of hitting the intake maifold

5 Answers

  • 6 months ago

    Plug the vacuum hose.

  • arther
    Lv 4
    6 months ago

    assuming you have the vac line pluged up , if its not pinging its head off when you try drive it when you have the distributor advanced to the point of the vac advance is hitting the inlet the distributor is probably installed wrong pull it out and reinstall if its an electronic on an old motor that started its life with a points distributor you may need to backwards so you can advance it up enough.

  • 6 months ago

    Unplug the vacuum advance and put a little nail in the line so it doesn't suck air does it Miss after you do that? If so that is the sign of a timing chain that has stretched. If I was you I would get ready to have the timing chain or the timing belt break and have to replace it. When I'm doing timing I take the vacuum advance off and use a timing light and put it like 5° advanced past top dead center. Then I put the vacuum timing back on and see how that feels if it lacks power then give it just a little more advanced.

  • Nancy
    Lv 6
    6 months ago

    It's normal for it to start running rough. If that's what you mean by "miss," then, yes. If you mean "miss" in the sense of certain cylinders not sparking at all, no.

  • How do you think about the answers? You can sign in to vote the answer.
  • Anonymous
    6 months ago


    It will make the spark too early, which effectively increases the compression ratio.

Still have questions? Get your answers by asking now.