Sometimes you can get oil in the spark plug holes due to leaking valve cover gasket. Usually spark plugs are replaced at the same time as coils since you're already in there and plugs are cheap. Hope it is plugs though.

Hey,
So like I said I replaced the coils then went ahead and replaced the valve cover gasket, and after that the car ran terrilble, it shook like crazy and stalled at every intersection and nothing I did helped, I replaced the spark plugs and still nothing. then I found the pvc hose behind the valve cover that was broken and not creating suction. replaced that and runs great. but still doesn't help the jerking when driving. I have now replaced the coils, plugs, and diagnosed many other things. someone said a dirty valve body spool, where is that and is it hard to do? is this an injector thing? there are no codes whatsoever except the o2 sensor which I have ordered and will replace. I doubt the tranny fluid has ever been replaced. im guessing that should be done? the car is at 187,000 km and ive had it since around 186,000km
thanks again for any input

ya too bad your mechanic told you to replace the coils and plugs. idk why he would if there was no misfire codes. if its misfiring bad enough to replace coils, it would throw a code so that was kinda stupid of him to suggest. plugs not a bad idea since its general maintenance, but not the coils.

as states previously, it really sounds more like a transmission issue. check the level to see if its low. but still better off draining and replacing the fluid. checking the level will just give you an idea if its slipping because its low. but id still drain n fill either way. especially since you dont know if its ever been done.

Hey so I finally figured out the problem, like you said I topped up the tranny oil and its good ( I will be doing a drain and flush)
anyway, that wasn't the problem. it was the 18 inch wheels, or maybe not because they were 18 inch but the one got a flat and I put the spare on and problem solved. drives as smooth as anything. turns out the rim was cracked, I bought these 18 inch M3 rims with low profile tires about a month ago and now that I think of it its been doing it ever since I had them on. I feel so stupid now. but it still has me baffled. was the crack in there the whole time? Im now looking for 19 inch wheels. the car is supposed to have 17in. will it ruin anything if I have different sizes? I was told that 16in will ruin my car. should I stick with 17in or can I go 18 again or what I really want, 19in
Thanks

Since you have xDrive, just be sure that the outer circumference of the tires is the same on all 4 wheels. The owners manual states that there can only be up to a 1% difference in tire circumference. If the circumferences are off by more than that I believe it will put extra stress on the xDrive transfer case because the clutches will have to constantly slip since one axle will be spinning at a different rate than the other. This has nothing necessarily to do with wheel size, but circumference of the tire.

Ah okay got it. so as long as all the tires are the same
thanks

Or staggered with the same OD and different profiles (wider for the rear). But this is for aesthetics and will aggravate the already understeer-prone nature of your handling.