Running rough

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