Oil cap and dipstick covered in creamy sludge, is this breather prob as not losing any water

Recheck the water pipes it might happen that there is a small hole that leaks when the engine runs.

have a coolant pressure test done and if you are not holding pressure there is a possibility of a leak in the housing behind the water pump
dew and gunk in the breather are indicators of water in the oil

So it's not the head gasket? And you are still losing coolant? Well, okay, you will have to find how the water is getting into the rocker, and whether it's your lost coolant or plain water. IDK, possibly an intake manifold leak?
Even though the oil looks clean, the water and gunge in the rocker area will drain into the sump and contaminate the oil. If it's not the coolant, run the engine until it is hot, then give it a few minutes for the oil and water to drain down from top of the engine into the oil sump. Then change the oil and oil filter. Good luck, hope you find the problem.

If the car is used mostly for short trips, a creamy oil cap is not unusual. Try to use this car for the occasional long trip to dry it out. The concern is that the oily sludge will fill up the tube that runs from the front corner of the valve cover down to the crankcase ventillation valve under the intake manifold. If that hose plugs up (typically only happens if the sludge freezes) the system can start sucking oil up through the oil drain from the crankcase ventilation valve and pumping it into the intake manifold. This problem is rare, usually seen only in 6 cyl BMW SUVs that are used for running errands in mountain communities and never really warm up, but it can happen if you have a lot of water/oil sludge buildup.
The rest of your problem statement is not completely clear. Missing a cylinder when cold is very common and may be caused by any one of several problems. If it smooths out after a minute or two, it is not a big concern. If the car misses on a cylinder after it is warm, check the age of your spark plugs, they should be replaced every 50k miles or so. Try pouring some fuel injector cleaner (Techron is the most popular) through it. A weak coil is also a possibility Early e46s had some coil problems, but I would expect that if you were going to have coil problems, they would have flared up long before now unless this is a really low mileage car..
The reference to odd puffs of smoke is a little unusual, but it is what reminded me of the possible problem with sludge plugging up the crankcase vent line. I suggest that you pull that line off the front of the valve cover and look inside. If it is full of sludge, get that system cleaned out.

The white creamy solution is oil mixed with water. Take out your dipstick and check for the same substance, if so, you have a blown head gasket. If not, it's just condensed water in your valve cover that mixes with the oil, witch isn't really a problem. Have a nice day!

If there's no oil cap directly on one of the valve covers (it may have a breather hose attached which connects to the breather element in the breather pan), then some models require adding oil through the dipstick. If this is the case, there should be a cap type dipstick instead of the standard "hook". There are 6 different motors (8 including variations) for your truck so no manual has the exact location of the oil cap. Best of luck and hope I answered your question.
Greg

hate to be the bearer of bad news, but i think your head gasket has failed causing the oil & water to mix in the engine. usually, the water enters the oil causing the milky cream liquid (check the under side of the oil fill cap for this same creamy liquid) and you wind up adding coolant since it gets low.

if the coolant is not getting low, then it may not be anything to worry about. in the colder months, BMWs have been known to display this creamy liquid on the oil cap. it disappears when the weather gets warmer. BMW has a service bulletin on this.

have a compression check done on it to see if this is truely the case. i hope i am wrong. and 1 pint every 2-4 thousand miles is not too bad.

hi if you have creamy scum in your oil then it sounds like you have a bad head gasket.the coolant is mixing with your oil if still under warrente i would bring to dealer to have fixed.

This really sounds like you have a leaky head gasket or worse, a cracked water jacket. You may be getting coolant into your crankcase, which would "water down", so to speak, your oil and cause you to lose oil pressure. I do not know what you mean by your "oil registering fine". I presume you mean the level on the dipstick. Do you keep losing coolant? Is there any brown/white milky sludge under your oil cap or on your dipstick? If so, you most likey would have a head gasket leak.

Sounds like your oil leak is finding hot exhaust manifold and smoking/smelling. Make sure the oil filler caps and breather hoses that connect to the valve cover (Top of Engine) are attached securely. Try and determine exactly where the oil leak originates [Valve covers - top side, oil pan - underneath, or shaft seals - front and rear of engine, or left and right ends with the sideways (transverse) engine mounting]. Also check oil level - a blown head gasket or cracked head or block could lose coolant into the oil reservoir, causing an overfilled and thus leaking situation... this will show up as a creamy looking substance on the dipstick. If the engine is not making any other signs of abnormality, strange knocks or clicks, overheating, or losing gross amounts of fluids, make sure it has enough oil in the crankcase and drive it to a reputable mechanic for a true evaluation of the problem.