On my E46 323 just recently my engine light came on, and then went away but now it is on again all the time and now I have a has a misfire and rough idle. So I decided to pull the codes and came up with p1188 and 1189 along with the cylinder misfire ones. Through my little bit of research I get "fuel control bank 1 sensor 1" and fuel control bank 2 sensor 1". Would this be my upstream o2 sensors needing replacement or would there be a simpler fix? I already plan on a fuel filter change and have cleaned the MAF and air filter.

What are your thoughts?

Aged pre-cat O2 sensors (the ones between the catalytic converters and the engine) can cause those codes, but so can an intake leak, bad MAF, or bad CCV. The useful life of the pre-cat sensors is not more than 100k, so if they are of that age or older they need to be replaced whether they are the cause of this fault or not.

Well, I changed both pre-cat o2 sensors, new plugs, checked the intake tract an don't see anywhere any cracks or possible leaks and everything is tight. The engine will still misfire and run rough. Is there a check I can do to with a multimeter to see if the MAF is operating properly? The misfiring is not constant, sometimes it is good and other times it will have a miss and no power, but occasionally I can just shut the engine off and restart and the problem will go away for a while.

I had an 3.0 X5 a few weeks ago with similar fault codes. Fuel trim too lean for both bank one and two. After smoking the intake, checking fuel pressure, I futher examined the additive and multiplicative values. They were a bit off. Ended up replacing the MAF.


You need to smoke the intake first though. DISA valves, crack pipes and throttle boots are common sources of small leaks.