oil pressure switch.
 

where is the oil pressure switch/ censor on a 325i? i want to clean it to see if it will fix my acceleration problem instead of changing my fuel pump, cause i think its either/or on where the problem lyes.:drummer

the oil pressure switch won't effect the pumps "running" ability. If there is no oil pressure or the oil press. switch is bad the pump won't run. IT's a total on / off issue, for situations as roleovers & crashes.

oh ok. well what do you think the problem is? cause sometimes ill turn it on and it will idle really low- like around 4 to 5 hundred rpms and itll even die sometimes. and it wont have any acceleration. ill hold the pedal to the floor and wont top 10mph. then all of the sudden itll take off and throw my head back and i wont have a problem. itll puff out that bluish white smoke and stuff. the head gasket is only 2 months old so it cant be that. what do you think?

It could be alot of possibilities - especially since you mentioned head gasket was recently replaced. Run a good fuel system cleaner through it, then replace fuel filter. Also check ALL your vac lines and the air intake boot for cracks /leaks.

BMW has a new Cleaner for your fuel system, it is recommended you
use it every 5k miles.
Also check for broken vacuum lines or perhaps even your idle valve.

Hope this helps you...

Luke /Moondawg57

cool, ill do all of that. its probly the fuel filter now that i think of it. but it probly would be a good idea to check all the hoses. as long as it dont turn out to be some huge expensive problem then ill be alright. haha. but i appreciate the advice guys.