Do mudguards affect fuel consumption

Go for it. I have them on my car and I didn't see any change in mpg. Some people may argue that theoretically will have some effect. I personally don't think it makes any difference..

 

Here's an earlier thread on this.

For the most part, there is little direct evidence to support the idea that
mud guards will hurt MPG much.

 

They come standard on priuses in Canada.

 

The mudflaps have to reduce MPG because of increased wind resistance, but it isn't easily measured or noticeable. I compensated for the mudflap loss by installing a shark fin antenna, which has less drag than the stock one.

The next thing to consider is how much MPG loss there is by turning on the headlights?

 

I'm sure you meant "wondering", not "wandering". But the short answer is no. While yes they do add drag, which does increase fuel use, it is very small and not enough to notice.

 

No change, tyre pressures are way more important.