I just bought a 2011 Volkswagen Touareg 3.6 FSI with 90,000 miles. After a couple of weeks of use, I had issues with the oil cooler, which caused oil to enter the cooling system. Now that it has been replaced and I can finally test it properly, I've noticed that one tank of fuel (approximately 20 gallons) gives me around 186 miles. The average fuel consumption is 7 MPG with city driving and staying below 2,000 RPM. Is this normal, or could there be an issue with my SUV?