Here's the whole picture:
cleaned maf, throttle body, drove a few miles and did an oil change/trans fluid/pan/filter service, drove a few miles home and parked. Then I fired up the vehicle to go somewhere and got a smoke show. Checked and found that I hadn't put the oil cap back on.. put that on and drove a couple miles, by which point it wasn't smoking as bad but it threw a lean code.

Could the oil cap have had anything to do with this? When I filled the trans I had the vehicle idling and I didn't see any of these symptoms, and the cap was off at that point. It was also off for my initial drive home, no smoke - I just noticed a crappy idle.

I cleared the code and it didn't come right back, but I haven't driven it again yet. I'll check all my intake connections again tomorrow but I would think that have shown me grief on my way to the lift garage..

this thing is pissing me off

 

You could have pulled more than the normal amount of oil into your intake causing the white smoke. Check the PCV to make sure it is not full of oil.

The unmeatered air may be causing the lean code.
What are the long term and short term fuel readings at idle and 2000 rpm?

Don't give up just yet.

Jeff

 

I'll check the pcv, can't tell you about the readings as I've only got a code reader.

 

What part of the pcv should I check and how should I go about it? I don't want to force any of those connections and break something.

I drove it around for a few min this morning, it puffed some smoke on start-up, then was ok. The smoke was back by the time it warmed up though. Running ok but definitely not quite right. CEL didn't return.

 

Checked the pcv lines before and after the throttle body and they're bone dry. The line that goes from the pass side valve cover to the intake manifold, however, is wet with oil. The valve cover end terminates in a small pancake shaped manifold. I'll open that up after a while and see if it needs to be cleaned out or what.. for now I'm gonna go drive the Caterham

 

The pancake is the PCV valve.

 

Abran, can I clean it up? Or should I plan to replace it..

 

You should replace, If it fails your engine is toast. Not expensive.