High rpm idle, no gauges, white colored exhaust

Hello. This is my first post here and I am totally baffled as to what my 98 4.0 is doing.

I have been building this jeep for a little over a month now. Up until this past weekend I had the gas tank dropped and both manifolds out to fix a cracked exhaust. I have also changed the clock spring.

I put everything back together yesterday. When I start up the engine it immediately revs up and holds there. Not sure what rpm because nothing on the dash works. I have cruise control and replaced the clock spring with one that was not set up for cruise control (got it cheap). I checked the fuses and they are all fine.

While it was running, I checked the throttle body to see if it was stuck open. It was closed. Which leads me to believe there could be a massive vacuum leak somewhere. Nothing obvious is popping out at me though.

Also, whitish smoke is coming out. See this pic: http://imgur.com/wxvuBJV

I am no sure but I think the exhaust may smell a little sweet. It could be in my head though. IF that is the case I would assume a coolant leak. But, I changed the oil while I had the manifolds off and the oil showed no signs of coolant.

I have searched around on many forums and found a diagnosis for each individual symptom but not for all of them combined. None of this was happening when I bought it 6 weeks ago.

Can someone point me in a direction to start diagnosis? The only thing I have thought to do is check the TPS voltage which is reading at around 5 volts.

Not sure on the RPM's, maybe HVAC vacuum leak?

...I had the mystery white smoke caused by a small leak (when the engine got up to temp) in the back of the valve cover. Drove me nuts for months! The oil was working it's way down and dripping onto the cat.

go back and check all your vacuum lines and fittings. ignore the white smoke for now, it may just be condensation blowing out of the exhaust because it has been sitting. it probably does it every morning and you never noticed it.