Hey fellas,

Problems with my car was that my fuel consumption has been more then usual @ about 18l/100km around town and 12L/100on on the highway. After giving it a spirited drive or where a high load on the engine had taken place i would come to a stop and the car would idle at around 500-600rpm with puffs of black smoke coming out the tailpipe.

So this morning i did some diagnosing on the e34 535iA and my o2 sensor signal is showing a steady 0.42v...... this is meant to fluctuating between 0.2-0.7v right and if its at a steady voltage then its toast? Creating a rich or lean situation didn't change anything. It didn't even change at different rpms. On a lighter note, the heating element seems to be working good.

Now I've sourced a replaced o2 sensor, a bosch unit, for about AUD$130-140 which seems to be cheap around here and im going to install this thing myself. Now how should i go about replacing the sensor? Drop half the exhaust? Or all? and what anti-seize stuff should i use on the sensors threads?

Keep in mind that i've changed spark plugs, fuel filter, fuel pump, vacuum hoses, injectors, adjusted AFM, so ive pretty much eliminated those options.