While I'm using my buddy's 2007 Silverado Classic (4.8L V8), I'm trying to fix some things up so I can return it in better shape than when I borrowed it.
For years, this truck has sufferered from what I've seen referred to as GM's Tap Syndrome (or some other cute desriptors). The noise is not nearly deep enough to be a knock and it definately isn't a ping... however, it sounds pretty severe as a "tap". The truck can run dozens or hundreds of miles and sound just fine, then, slowly, the tap starts to fade in. Aside from it raising concern and sounding terrible, the engine powers on.
We've tried all of the BS solutions like SeaFoam or Trans Fluid shortly before an oil change as well as clearing the computer both with a handheld and by disconnecting the battery. .
I do have an active CEL for Knock Sensor #2 (if I remember correctly), but I'm told that could be common on these trucks because of damage over time to the harnesses that lead to those two knock sensors. Unfortunately, they are under the intake and mildly pricy. As I understand it, this could be an entirely unrelated issue from the tapping. In some cases, you can tell that the timing is being retarded while the CEL is active to prevent damage.
So, the question is: has anyone had first-hand experience with this beast, and what was your outcome? Any advice?
Thank you
Jimmy
For years, this truck has sufferered from what I've seen referred to as GM's Tap Syndrome (or some other cute desriptors). The noise is not nearly deep enough to be a knock and it definately isn't a ping... however, it sounds pretty severe as a "tap". The truck can run dozens or hundreds of miles and sound just fine, then, slowly, the tap starts to fade in. Aside from it raising concern and sounding terrible, the engine powers on.
We've tried all of the BS solutions like SeaFoam or Trans Fluid shortly before an oil change as well as clearing the computer both with a handheld and by disconnecting the battery. .
I do have an active CEL for Knock Sensor #2 (if I remember correctly), but I'm told that could be common on these trucks because of damage over time to the harnesses that lead to those two knock sensors. Unfortunately, they are under the intake and mildly pricy. As I understand it, this could be an entirely unrelated issue from the tapping. In some cases, you can tell that the timing is being retarded while the CEL is active to prevent damage.
So, the question is: has anyone had first-hand experience with this beast, and what was your outcome? Any advice?
Thank you
Jimmy