Hello, im looking for any tips i can get on what the issue is. At around 5500 RPM the car seems to lose power. For more info: It an 07 series 1, 90,000 kilometres, has recently new plugs, coils, leads and recently cleaned the ssv. Have looked at it possibly being the catalytic converter but the power seems to inconsistent past 5500, but its still possible. Also looked at possible fuel pump/filter being the issue. Anyway i just wanted a second opinion on what the issue could be, thanks.

In the video im using half throttle during acceleration without any fluctuations in pedal movement.

 

This may be a nonstarter, but have you checked the MAF? I had a similar issue where the threads holding the MAF in the stock tubing were stripped which seemed to cause issues at certain RPMs & loads. From member it was near 5k and ~7.5k under heavy load. Maybe a simple fix.

 

Ive cleaned it before and i didnt notice any stripped threads, but i might double check to be certain. Thanks

 

Verify the cat. It might not be the problem but if it is you'll be shopping for a bew engine soon.

 

Fixed it. Honestly embarrassing, turns out two spark plug wires came loose so it was igniting either at the wrong time or not fully igniting at all causing the power loss and the stutter. But it was an easy fix at least!

 

Thanks for the update.
Not enough people do this, happy to hear it was an easy fix.