I have 275K miles on my Expedition. I've recently had a rough idle; like panting up and down and sometimes surging. It drives fine. I've read several great threads about causes: dirty TB, dirty MAF sensor, exhaust leak, vacuum leak, dirty IAC. I was going to change the common culprit; the IAC, but on the 98 it's tight quarters even though its 2 bolts and a connection.

Yesterday I looked for a vacuum leak, found none, but doesn't mean it's not there. Changed the PCV valve, and cleaned MAF sensor. I cleaned the mouth and plate of the throttle body while attached with the appropriate cleaner. When I turned it over and brought it up to operating temp, I now have a high idle (1000 to 1200.)

I noticed a seam leak in my muffler. Could this be the problem?

From what I can see, the TB is real dirty. I want to remove the TB and adapter and IAC all at once (4 bolts and vacuum lines etc) and thoroughly clean the TB, change the IAC and inspect the latent vacuum lines.

My question: Is this doable or would you advise not to? Can I take this all out as one unit and work on it on the bench rather than tight quarters or will the fire wall prevent me from removing the bolts?
Are there other possible causes anyone can think of? Any insight would be greatly appreciated.

[/I]Thanks, Kurt kgparry04@yahoo.com