At cold, the idle tends to surge up and down for about 10 seconds. More prevalent with ac on, but still happens. It seems to happen now too as I come to a stop. The car is a 6 speed manual so that's in neutral.
I have cleaned MAF (which was not even dirty), new air filter, and ran a couple bottles of Techron engine cleaner. I want to see if my throttle body is dirty this weekend.

 

any codes? scan even of no CEL.

 

no CEL. took it to advance and he pulled up no codes.

 

Cooper or S?

Some Coopers have a lumpy idle at first start, could be the VANOS sealing rings are worn or the cam caps have excessive wear and the VANOS solenoids aren't pumping up as quickly as they should.

The generic code reader at the parts stores almost never tell you the whole story, you need to find a quality tool get information from.

 

Base Clubman. I ordered a throttle body gasket to do this next weekend, as much as I wanted to do it this past weekend.
The CEL blinked a few times today, but the parts store says it needs to be a standing light to get a code.

 

The codes are stored until cleared, you need to find a better scan tool.

I've never seen a throttle body gasket fail on these cars, I would say you've got other issues. The vacuum system is extremely simple on your car, I would more suspect a VANOS fault or timing chain if you feel it's a problem like a vacuum leak.

 

right. I mentioned I wanted to clean the throttle body. VANOS is a recent new part. it was surging at idle before and after the replacement. if it was vacuum, wouldn't it be idling high? how can I test the vacuum pump? i have a gaug. can I just unplug a line and see if it holds?

 

If you had a vacuum leak the car would idle rough, want to stall (depending on severity), but as you came out of vacuum or began to build boost the problem would become smaller or even go away entirely, until you again come down to idle.

You could put a vacuum gauge on the outlet of the vacuum pump, but the vacuum pump only works the wastegate vacuum supply and brake booster, that won't give you much information on a manifold vacuum problem.

 

I was able to borrow a friend's Mac scanner, but would you believe the car isn't doing it now for me to pull up a quick code? I kept it plugged in while driving and nothing.

 

That scanner may not support manufacturer codes, you'll need to find a scan tool that will read manufacturer codes; Snap-On, Autologic, Auto Enginuity, some Autel units, ISTA, etc.

 

Update:
I took a look at the plugs and all of the porcelain were oily, especially #4 and they were loose as well. I replaced the plugs and valve cover gasket this weekend and all seems to be great now. Someone just siliconed around the spark plug towers and it eventually leaked.
Can you recommend me a scanner for the car that won't kill my bank account?