Hello all. I have a 2006 JCW R52 and have been steadily replacing parts looking for a power surge issue. Basically, the car runs very well, except when I get to about 5500 rpm, then I get a power loss all over the car, but the motor still pulls. My gauge needles drop to zero and reboot, my interior lights kick off and reboot, my radio cuts off and back on, my power steering motor cuts out and steering becomes very still for a few seconds, and no codes are thrown, and my headlights don't cut off (xenon).

I have replaced all pulleys and the serpentine belt, just replaced the passenger top motor mount. Alternator always gives a good charge and I have checked the battery terminals, which are tight. All my fuses are good. Have not checked the 42 pin connector yet, but I'm trying to get opinions before I do that.

Anyone else ever heard of this issue?

Thanks in advance.

 

Have you checked your belt tensioner? Can you see the hole in the tab? Have you checked for thrown codes?

 

The belt tensioner is brand new. Was surging before the replacement, and after. I have checked it with a cheap phone OBD scanner, but it didn't give me anything related to the issue. However, I did do the scan before I ever noticed it happening, shortly after I bought the car a few months back. I will try it again now. Problem is, no warning lights show up after it happens.