AFR weak on cold days

[markbudgen]

Guys,

I have a Porsche 993 driver with a supercharger on it. Not pushing anywhere near as much power as some but as I've used this site for information so many times I have a question that I hope someone might be able to help me out on. Car runs fine in warm weather O2s around 800 with a 50:50 mix of methanol/distilled water injection based on a souped up 1S system. I have a pre-race pump priming pump and a 2 stage injection system. When it gets cooler say below 10C the AFR soars off the scale (weak). I'm not sure if it is a side effect of the methanol/water injection and to be expected or its a real issue. Car runs fine but the AFR tells me something is amiss. Tried lots of things, temperature sensor, fuel pressure, all spot on. So i'm left with this being a side effect of the methanol injection or the Air flow meter. So my question really is would injecting alcohol on a cold day cause the O2 reading to read way to weak when in fact it is ok?

Many thanks for any help you can be, Mark.