all these problems lately <:C where to start?

[[1990]525]

1990 525 m20b25 Today my oil pressure light (red) has been coming on @ idle, revs dropping below 500 then throwoing up to ~700 back and forth while I idle. The light flickers on and off during this period (not steady). Dipstick says oil level is normal. I had drained about a litre of oil 2 weeks ago because it was showing VERY high on the dipstick.

Is it possible my dipstick lies to me? Should I run seafoam through it and do another oil change soon going back to Mobil 1?

It also has been losing power for seconds at a time during normal driving.

Where should I start?

Perhaps take into consideration these problems:
http://www.bimmernut.com/forum/showt...lol-que-sludge
http://www.bimmernut.com/forum/showt...olant-troubles