1. Welcome To GMTruckClub.com!

    The #1 Chevy Truck Forum Online
    Online since 2004, we are the #1 Chevy Truck & SUV forum and user community. If you have any questions about your Chevy or GMC Truck, SUV or Crossover, or just want to connect with other GM owners and enthusiasts around the world, you've found the best place on the internet to do that.

    Join Today ~ It's Free
    Registering is Free and Easy! Hope to see you on the forums soon!

Timing issue?

Discussion in 'GM Powertrain' started by BurbanMan, Jan 29, 2014.

  1. BurbanMan

    BurbanMan Member

    I recently replaced the intake gaskets on my wife's 99 Tahoe (5.7/auto). After doing so I had a reputable shop set the timing since I don't have that fancy computer. Now 3 days or so later the "service engine soon" light comes on. The truck feels like it has not low end guys at times. This sounds like timing issue to me, but I would like a second, third, or 100th opinion lol Here are the codes that we pulled: p0420/p0430. I've read that these are generally O2 sensor or cat converter issues, but again I would appreciate confirmation from those of you more knowledgeable than myself. Thanks in advance!

    Attached Files:

  2. BurbanMan

    BurbanMan Member

    Dang. Nobody has any ideas?
  3. dpeter

    dpeter Member

    Intake leaking?
  4. BurbanMan

    BurbanMan Member

    no coolant in the oil or vice versa, and I haven't spotted any fluid seeping. I've been keeping a pretty close tab on it for about a week
  5. Conlan Rose

    Conlan Rose Super Moderator 1000 Posts

    Before the intake replacement was there oil or coolant getting in the the cylinders? Either burning can quickly damage the Cat or the O2 sensors. My Tahoe has that code because of a bad cat which I'm replacing in June.
  6. Pikey

    Pikey Moderator Staff Member ROTM Winner 1000 Posts

    Just for the heck of it I would take a can of carb cleaner and spray around the intake while it was running listening for rpm increases.
  7. BurbanMan

    BurbanMan Member

    Yes, there was coolant in the oil

    I'll give it a try

Share This Page