Idle rpms vary, why?

[JRSRIG]

Good morning, all! I have a question about my engine idle. I have an 02 F350 automatic and the idle drops and increases while in park. It happens after it has warmed up and randomly. I have already experienced a CPS failure and installed it last week (immediately went to dealer and bought another) and would like to know if there is something else I should be looking at for this? It doesn't seem right that, with all the electronic controls on these newer vehicles, it should have a varying idle.

Thanks for any ideas.

JR

[jfines@cox.net]

Well first thought for me would be a CPS. Then second thought, My truck does that too, to some extent. But I've figured that mine is due to the A/C.

I live in the desert still so I'm still using it. Best way to tell, is to pop the hood and watch to see if anything is cycling.

As for anything else, I'm at a loss. And here is a bump back to the top again.