Running lean on one bank only...!

Can you substitute the ignition coils on that side one by one? If it’s like the x300 it doesn’t throw up a code but runs rough. Under load the coil breaks down.
Regards John
Apologies. Just noticed you did them

I zero’d the fuel trims and ow with the new MAF its gone back to its old tricks showing random misfire on all cylinders on bank 2. I monitored the trims while driving to and from work. In cruise bank 2 are negative up to around -12 and bank 1 slightly positive, at idle they are virtually identical and where they should be, however if I just blip the throttle bank 2 STFT goes up to -20 whereas bank 1 STFT goes positive as you would expect. So I am trying to determine what would cause overfuelling i,e. low oxygen content driving the ECU to think it needs to reduce fuel delivery with high negative fuel trims, I wouldn’t have thought there was enough gas flow at 1500 rpm for a blocked cat to cause this seeing as I have driven it at 80 mph without the trims being this high in negative numbers. In fact the only time bank 2 STFT goes positive is on overrun when the injectors should not be delivering any fuel, so maybe this points more to an injector hosing in fuel? I am going to try just plugging in the original upper O2 sensor I took out into the harness to see if reading atmospheric oxygen levels will force the ECU to add fuel to bank 2 giving positive fuels trims, hopefully to find out what the ECU is basing its incorrect calculations on. Will report back.

Good luck, although the cold O2 probe will probably read off limits and as such throw a code and that’s it?

I don’t know if a clogged cat can be measured with a temperature gun. That‘d be worth a try. A cold exhaust behind the cat maybe.

Did you ever get STP for the fuel tank, to keep the injectors clean ?
At least once a year?


Yes, I regularly use injector cleaner in my cars.

And I know nobody who does - no issues :rofl:

Any new developments?

Hi David, thanks for asking. I tried a used fuel rail and injectors at the weekend but it ran worse so refitted the originals.I am now trying to locate a catalytic converter as this is the only thing left.

Good, I sure hope the cat fixes your problem.

If you have the time and spares are rare you could unbolt the cat and look inside. It may be illegal to drive without cat so keep that in mind. If the matrix has broken up or it is clogged up you will see.
Maybe you have shops in Norway that replace the element and weld it back up; we have that and it’s even legal. And not as expensive (maybe outside norway)

I am trying to source a new catalyser as here we don’t have all the repair services you guys have, Norwegians don’t fix things they just throw them away and buy new!

I live in Germany and I was surprised that there’s such a company here!