Rough Idle on 2000 4.0L

I have searched and havent quite found anything the quite resembles my problem. First i have a 2000 4.0L,AW4,NP231 w/ 55K Recently within the past three days it has had a problem upon start up only after the engine cools it turns over like normal but it idles very rough for almost a minute each time the idle can reach nearly zero to under 800 or so, if i try and drive the jeep before it settles out it lags and sometimes lets out a loud pop noise to a clunk of some sort. but only in the first minute or so. After that all is fine and there are no problems when starting it when its still warm. THe searching i have done leads be to believe that tomorrow i need to check the TB for cleanliness and possibly a bad TPS or IAC as well? I just wanted a second opinion or two before i start into this thank you for your time. -steve

The first thing I would do to diagnose this is to put a fule pressure guage on the rail befire you shut the engine down. It should hold pressure till you start the next time. If it doesn't either the regulator/filter assy. at the tank is bleeding down or an injector is leaking down. This will cause either a flooded condition(injector) or no fuel(reg.) at startup, either of which will cause erratic idle, stumbling, etc.

It sounds to me like the fuel pump check valve is malfunctioning causing a loss of fuel pressure when the vehicle is left standing for a while. To confirm that, check the fuel pressure at the injector rail when you crank up the engine for the first time. The fuel pressure should not fall below 30psi less than five minutes after shutting the engine off.
There's a TSB about this problem so it seems to be quite common.

http://www.wjjeeps.com/tsb_list.htm#FUEL

Its been a few days and the problem seems to be getting a little better i was told i could unplug the IAC and plug back in that has helped some but i have noticed my gas mileage has also dropped 25 miles to the tank. On top of that when idle'n rough if i apply gas i see white smoke at the tailpipe. any new ideas? i'd hope to avoid taking this somewhere but its getting worse....