Reduced miles per gallon

my 03 murano with 55,000 miles used to get 28 mpg on interstate at 70 mph. On a recent

trip I got only 21-22 mpg. Serviced per the

Nissan owner’s manual. Last service replaced all under the hood belts.

How long was your trip?
What type of driving?
How was the mileage measured?
Was the Murano loaded for the trip? Is it usually?
Have you checked your tire pressure lately?

There are tons of possible reasons for mileage variations, but variations in driving conditions, variations in load, inaccurate measuring methodology, and low tire pressure are the most common reasons.

According to the revised EPA numbers, your vehicle is rated for 18 city/ 23 highway. 21-22 MPG seems perfectly normal. Make sure you are using premium fuel. The VQ V6 was made to perform best on 91 octane or better. It will run on 87 octane, but the decline in power and mileage is more noticeable than most other engines that “recommend” premium fuel.

I think my mileage issue was indeed caused by my switching from 90 to 87 octane.
I will switch back to 91 & see what happens. Thank you for your injput. murano