Hey guys. Any ideas what would cause the engine to rev really high after it warms up?? It idles normal when started, but will eventually rev up and won’t return to normal idle until it has completely cooled down.

 

Sounds like a vacuum leak, check all lines, check manifold nuts, and verify your EGR doesn't have a leak.

 

ok. So I checked for vacuum leaks, tightened the manifold bolts, and changed the engine coolant sensor as well as the electric fan temp sensor. Problem is fixed so not sure exactly what fixed it. But the temp sensors were factory. Thanks guys