[2000CAYukon]

I would also suggest to replace the PCV gromet if it is hard and not sealing well. This made a big difference on my 90 GMC K1500 5.7.

A high idle could be a vacuum leak. The TBI Base gasket was a common issue with the original gaskets. Check the vacuum lines to the MAP sensor. I leak in this line will cause the ECM to think the engine is under load and give the engine more fuel.

A bad engine coolant temp sensor can also cause a high idle. If off enough, it will cause a check engine light.

//2000CAYukon