I wouldn't give up quite yet, but that's up to you.
Intake leaks are the common cause of fuel mixture codes...and the oil level light is unimportant, though you should, of course, make sure your level is correct when the car is cool and level.
Also, I'm only one guy...others here can help too, and will, if you don't seem so eager to get to a shop. They'll read that and just not bother helping in many cases...just saying.
I'm so depressed. No one wants to come see me in NYC: Sat, Oct. 8, 6 p.m. at Greenwich Village Comedy Club.
Mangofy your E46!