kaysha241
TYF Newbie
So my Yukon has had a little tick that has been there since 90k. Not really noticeable unless you floored it and then you could barely hear it. It now has 250k. For the last couple of weeks whenever it would downshift, and RPM increase, you could hear it a little more and the CEL would flash a little. A couple of days ago, when it downshifted it did the same thing and then started to run crapy. As I got off the freeway, waiting at the light, it would barely idle. A few times over the last few days it stalls, continuously poor idle, and rough running along with CEL light on and flashing once i get over 30mph.
1st thought is PCV hose so I checked it, but it is on and ok. I can hear a constant PSST, PSST, PSST, PSST, as it idles, coming from the intake manifold.
I have inspected it, sprayed carb cleaner around the base, and checked all suggestions I could find for potential vacuum leaks without removing anything.
The only other thing I can think of is to replace the intake manifold gaskets, thinking that maybe when it downshifted and drove up the RPM, it blew the gasket. I intend to do the valley gasket, knock sensor, and harness while I'm in there.
Is there anything I am missing that may be causing the rough idle, poor performance, and PSST, PSST, PSST, PSST vacuum noise that I can check before tearing into it???
Thanks - your experience and knowledge is appreciated!
1st thought is PCV hose so I checked it, but it is on and ok. I can hear a constant PSST, PSST, PSST, PSST, as it idles, coming from the intake manifold.
I have inspected it, sprayed carb cleaner around the base, and checked all suggestions I could find for potential vacuum leaks without removing anything.
The only other thing I can think of is to replace the intake manifold gaskets, thinking that maybe when it downshifted and drove up the RPM, it blew the gasket. I intend to do the valley gasket, knock sensor, and harness while I'm in there.
Is there anything I am missing that may be causing the rough idle, poor performance, and PSST, PSST, PSST, PSST vacuum noise that I can check before tearing into it???
Thanks - your experience and knowledge is appreciated!
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