mobile-menu-icon
GM Authority

Idles great, Runs awful cold, runs great hot

Viewing 0 reply threads
  • Author
    Posts
    • #516631
      Sierra2500
      Participant

      1999 Sierra 2500 6.0l Starts great, idles great, runs like crap cold on acceleration above 1500 rpm ( light or heavy ) . No power, back firing, missing etc. Runs great once engine temp hits 85C. I have replaced intake manifold gasket, MAF sensor, re-programmed CPS, checked EGR valve, fuel pressure is 60psi, replaced plugs and wires, vacuum is strong and steady, replaced engine coolant sensor. Any help is greatly appreciated. Thank you

Viewing 0 reply threads
  • You must be logged in to reply to this topic.

Subscribe to GM Authority

For around-the-clock GM news coverage

We'll send you one email per day with the latest GM news. It's totally free.