mitsumark

OK fellas..I got an 05 E55 with 78K on it...Has some basic mods that include EC ECU & TCU tune,,83mm pulley,,ARH longtubes w/no cats,VRP heat exchanger,VRP split cooling,Bosch 010 pump,,Yada Yada yada...Car has had recent NGK plugs installed...I've noticed since I've owned the car which is only about a month now,,the car seems to idle like crap at times ramdomly.It will be idling and then out of nowhere it stumbles..Almost identical to when you'd turn on your AC and the compressor kicks on...Well today I got the dreaded CEL....Ran the codes and got the PO130 & PO 150 which is the codes for both upstream 02 sensors..I've been wrenching for quite awhile..Although not on many Euros..It's usually basic common sense that both upstream 02s wouldnt fail at the same time..I have a feeling whatever is causing the rough idle is related to the 02 codes...Anyone have any ideas?...MAP sensor going south?..As stated I'm not getting any misfire codes,,plugs are fresh,,and I can't find any vac leaks...

AMG-SVT-FTW

May be exhaust leaks up stream of the O2 sensors throwing them out of range. Have you logged your fuel trims?

mitsumark

Haven't logged FTs but the longtubes are properly secured and I don't hear any exhaust leaks at all up there..

tw2

Maybe a smoke test. If you replace the sensors I would go OEM. They didn't extend the O2 wires with the header install did they?

mitsumark

I don't know..Would the 02 wiring have to be extended using ARH longtubes?...I'm gonna climb under the car tomorrow to see what's going on under there..It doesn't help the thing is Practically laying on the ground😯..

tw2

I don't know if it is required or not but I do know that it can cause problems if it is done incorrectly, seems to be a fairly sensitive system.

StarvingArtist

Just a guess, sometimes the plastic unused tubing plug at the back of the supercharger leaks at random. If you pull the SC off for bearing maintenance, eliminate it altogether.

MACEDON

Unplug your main battery for 30 minutes and plug it back in again. It resets the fuel trims. I had that code constantly until I reset the ECU with the battery and it has not appeared since.