My Jeep Grand Cherokee starts at an extremely high idle first thing in the morning. The idle speed eventually lowers but will then not be steady and smooth. Once I start driving it lacks power initially and sounds louder than it should. After a few minutes it seems fine again. I have taken it to the dealer twice now and they say they can't find any problems or readings from the computer. Any suggestions would be appreciated. Thanks.

Hmmmmm.....could be a loose vacuum hose.
That wouldn't usually register a trouble code.
Of the many other things I can think of, the TPS may be failing or have a loose harness.

what do u mean by LOUDER, are u talking about a ROARING sound (like the engine is pulling more AIR).

the unsteady IDLE, is prolly the IAC (Idle Air Control Valve (Motor). u may need to clean the Throotle Body also, if it looks dirty clean it the butterfly should be clean, this help air flow?.

if u need any more info or have a more detailed description email me Joe dksob81@hotmail.com

I have the same problem on my "99 GC LTD. High idle on initial startup,
settles down slowly, then uneven during driving. Also idles even higher
after engine is warm on later startups...as high as 3000 rpm. before settling down. No error codes from OBD, or check engine light. Hope this just means throtte body cleaning, or a hose.

also check to make sure all the vacuum lines (Brake Booster, PCV, etc) are hooked up and they don't have a leak.