2004 LS430 Running rough, using more gas

[Mile_High_Flyer]

Over the last few days, my LS430 has started running rough, and economy has plummeted. Idle speed can vary. Sometimes it will idle very slow, and run very, very rich. Rich enough to smoke. I found a pipe that had come out of the rubber tube connecting it to another pipe, so I joined them back. No change, MAF and Throttle body were cleaned about a couple thousand kilometres ago, as was the air filter. Not that they were dirty, they weren't, but just general maintenance. I was on about 1/4 tank of fuel, buit have filled it up, so it is most unlikely to be bad fuel. The trans is also not quite as smooth changing as usual, but it wouldn't be noticed by anyone else. The exhaust smells, which I assume is the Cat working hard. I have disconnected the battery for 30 minutes, to reboot the system, then run a 40km or so trip to try and reset the computer. Tried that 3 times! I hjave a HUD plugged into the diagnostic port, and it normally shows the same instant fuel consumption as the dash. However, at the moment it shows a bit higher consumption than the dash. There is no Check Engine light showing.

Any thoughts what else I can try?

Thank you.   Cheers, Keith.