Possible Fuel Leak Advice

[Temasterson]

For the last couple of weeks wife and I have both noticed that we are getting very low MPG.

Yesterday I clocked us doing 12 miles at average urban city speed, no heavy traffic. After completing those 12 miles the range meter that shows miles remaining until empty decreased by 58 miles.

I switched the engine on this morning and it had gone down another 2 miles. 

i know the range number is just an estimate and that it changes depending on recent performance, but we haven’t been on any long distance trips for months and I can tell by how often we need to refill that the MPG we are getting is not what we should be getting. 
 

I thought I had found a leak yesterday as  there was a drip coming from this tube (see picture) under the car. I collected a cup full of the liquid after 1/2 an hour, but it had no smell, so it wasn’t petrol. I also could not detect any smell of petrol when I parked up and went under the car.

Would you advise me taking it to Nissan or is this something that any mechanic would be able to find the problem? Thanks for any advice.

[Trevor]

The hose is air conditioning drain hose and emits water from the interior of the vehicle.

I would have the service items checked (e.g. oil, spark plugs, air filter, etc) at your local garage

[Temasterson]

Thanks for the info about the air con hose. Just to update - I haven’t got to bottom of the problem yet.
 

We’ve only used the car a couple of times a week recently. One day I noticed the range meter had added an extra 40 miles since the last time I used it, but then it immediately started reducing the range by about 4 miles for every mile I drove. I think it may have settled down a bit now. 

 

My instinct this could be one of two things - either range estimate is on the blink or the petrol we put in was very frothy / full of air. I’ve read bubbles in the petrol is actually a thing, so maybe it has taken a while to release the air and level out.