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vacuum leak

  1. Possible vacuum leak troubleshooting?

    So I have been noticing some rough brake performance at times, and an on again off again P0171 MIL on my 06 TB. It runs perfectly fine sometimes, but others it does. There's a small high pitched noise under the hood, not sure from where though. The brake booster isn't making any noise though as...
  2. Issue with vacuum leak, brake booster

    I've been doing some research, and I believe I have the problem figured out but I would like some input to verify the conclusions I've come to. I've been hearing a vacuum leak for the past few weeks, I believe the brake booster is the problem, specifically not holding vacuum. I can hear a...
  3. intake resonator box 02 envoy

    Hey guys hope you can help. I have a 2002 gmc envoy I6. When changing spark plugs I happened to notice on the right side of my intake resonator box there was a little nipple there that I assumed should have something on it.. However there hasn't been since I've owned it about 3 months now.. From...
  4. engine knocking, misfires, rattling rocker arms, oh my

    OEM Issues
    It started with my 05 TB turning on the check engine light. I checked the code, and it mentioned something about the knock sensor going off. I checked around and decided to replace the spark plugs in the truck. When that was done, I though everything was fine, except coil pack 4 and 6 didn't...