Hi everyone, new here to NAM and im also new to mini... owned the car since august. have a few things going on with my 03 MCS. She has just under 119K miles on her. Things i have noticed is a very large power decrease... seems as though the car has lost close to 50% power in all gears... no miss fires or engine burps... car runs great during normal driving. but once you go past half throttle there is next to nothing... started about 2 weeks ago... i reset the ECU as iv read that it can start to adapt to the way you drive and i don't normally drive it hard. car is basically stock other then M7 intake and straight piped. i did the exhaust about 3 days before i noticed the power loss... could this be lack of back pressure since the car is forced induction? also the car through a check engine light in regards to the front o2 sensor about a month ago but went back off about 2 days later and hasn't reappeared... could this cause the power loss?

now on to the second part... valve train is super loud... motor will remain loud cold and warm but if i shut the car off once its up to temp and restart it, it quiets down a bit. but still can notice the valves smacking around... could this be low oil pressure? or a bad oil pump? i run royal purple 5-30 full syn. in the car.

any help would be greatly appreciated as im pretty hands on and know my way around a motor. but figured id come here and see if anyone has had any of these issues in the past or present before i start throwing parts and time at it...

thanks much!
Brian

 

Bump

 

If the BPV (bypass valve) is stuck closed, you will have no boost. If you are good with wrenches, do a Youtube search for MODMINI bypass valve

 

The video is below. There are over 14,000 Gen1 Stock Problem/Issues threads. Have you done any searches?