Mine has a steady fast idle,making me think it's not vacuum leak. It started a few miles after driving 20 miles of badly washboarded dirt road crossing Carrizo Plains National Monument. It hangs steady after warmup at 1,400rpm.
.
Today I swaped ICS,
no change
Then I checked water temp sender,,,225 ohms with engine warm and running. That's alittle less resistance than specs., but should provide low enough to tell ECU that engines hot.
I unplugged terminal at sender and check engine light comes on after a minute, telling me that no wires are cracked and ECU is getting infomation from sender.
All vacuum hoses and vapor and egr solinoids are not cracked.
since the RPMs are real steady I'm thinking this is electronic,,,and that possibly the ECU board cracked with all the vibes on that road.
Late tonight I plan on swaping in a spare ECU.