What are the percentage values for the left and right banks that are displayed on the Self Learn Window? Last time I looked, the left bank was on 1% and the right bank was on -9%. Don't like the look of this.

I wouldn't worry about it too much.

It could be caused by a lot of things:

-fuel that isn't really up to spec

-injector, sparkplug, coil, ptu or o2-sensor that's not up to spec

-the right bank might not get enough air for some reason

-loose or corroded connector somewhere

 

I would reset it a few times and see if the left bank gets consistently richer compared to the right bank.

 

if it is, you could start swapping sparkplugs and coils from left to right and see if the readings for the right bank get higher.

 

-Eric

Thanks,

 

Odd thing is that it improved dramatically after I put half a can of WD40 into the Idle Air Valve to fix a high idle problem after adjusting the TPS.

 

One further oddish thing, I did a sensor log on a short run after fully warming her up. When accelerating the left bank alpha is always below 100% (Between 90 and 95%) and the right bank alpha is above 100% (between 95% and 100%). Does this indicate any problems? I'm still searching for the reason I've got b!"£Fr all power.

 

You won't notice a thing (powerwise) if the A/F alpha readings change...it's just used by the ECU to optimize the mixture.

but you could disconnect both O2-sensors and see if your problem becomes better/worse

 

I'm not sure what you have already tried and checked, but if the loss in power is that noticable I think you should look to other things..

 

-check the boostpressure with an aftermarket boostgauge

-check for clogged cat(s)...if you still have those

-look for serious boostleaks by putting the plenum and intercoolers under pressure

-check fuel pressure

-do a compression test

 

-Eric

Thanks for the ideas,

 

I don't know if the cat is clogged but it has definitely collapsed. If yoy jack the car up you can hear the contents moving around.

Thanks for the ideas,

 

I don't know if the cat is clogged but it has definitely collapsed. If you jack the car up you can hear the contents moving around.