Hello all,

I have a 2009 R57 with the N14 engine. I have been experiencing an erratic idle. If you give it throttle it smooths out over 2000 rpm. I have done the following:

New MAF
New Absolute manifold pressure sensors (on charge pipe and intake manifold)
New Vanos
New Plugs
New Coils
New Vacuum Pump
New throttle body
New valve cover
New PCV hose

All parts are OEM, and I have tested the air intake and chage pipe with a smoke machine. The only leak I found was from the PCV hose to the oil separator. I replaced that with an OEM hose. My short term fuel trims are wildly erratic. Fuel pressure good, no issues until about 45 seconds in when I get the symbol for reduced power. Then the surging begins, and it goes from 100 to 8-900 rpm. Eventually it will stall and be hard to start. I receive no codes except for super knock.

I'm literally at my wits end. Any help is appreciated!

Jay

 

In this thread, super knock codes were linked to a "small turbo vacuum hose".