Hi Kennithc,
More than likely you have a vacuum leak or unmetered air making it into the cylinders.
If you have a scan tool, monitor the fuel trims when the vehicle is acting up. I imagine they are showing a lean condition which would indicate a vacuum leak.
Also, do you have a 5.7L V8? I think this was the only option but I just want to make sure because they are well known to have intake manifold gasket leaks. They normally leak when the intake and head meet.
Here is a guide that will help find vacuum leaks but I would just use some brake cleaner and spray around the intake and listen for the RPM to come up. Or if you have a scan tool what the fuel trims while you are spraying and see when they go rich.
https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
Let me know if you have questions. Thanks
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Jul 13, 2019 at 12:17 PM
