Power loss

[titandavid2008]

Just bought a 2007 335i. 140000 miles. Has an oil leak, don't know where it is coming from, have an appointment to get it looked at by an auto shop. Before I discovered the leak I decided to take it on the highway, went to pass someone and had a loss a whole lot of power during near full throttle. Ran like a slug all the way home. Got home, and it is running rough as hell, seems like it is about to die. Any ideas?

I tried to look through the forums but I am impatient as hell.

[RocketSurgeon]

Something triggered limp mode, which cuts power and prevents you from making any boost. "Running rough as hell" sounds like a cylinder is shut off from a bad coil or injector. You'll need to pull codes to pinpoint the issue. BMW codes will show far more information than generic P-codes, though either could tell you which cylinder isn't firing.
To diagnose a bad coil, figure out which cylinder isn't firing, then swap that coil with another cylinder and see if the misfire follows.
A K+DCAN cable is the best $20 you can spend (get one with a green board and a switch). If you run android, the MHD app can let you pull codes for free.

[NeedForBoost]

When I bought my 08 335 just a few weeks ago 50 miles from home I told myself I'd take it easy on the way home til fluids are changed and I could get an idea of what it may need. Couldn't help myself, on my way home 15 minutes into the drive I laid into the pedal on the right, immediately It ran really rough and a couple ugly yellow lights on the dash came on I babied it home and changed the plugs a day or so later, they were old and worn out. Right away it ran great with the new plugs. Be advised tho, you need a special 14mm 12 point socket that has a reduced outer diameter at the end of it, basically a special tool. if you elect to do plugs, watch a couple youtubes and order the tool and plugs before you tackle the job.