* Engine size: The 1981 Suburban offered several engine options, ranging from a small-block V8 to a big-block V8. Larger engines significantly reduced fuel economy.
* Transmission: Automatic transmissions generally got slightly worse mileage than manuals.
* Vehicle condition: Proper maintenance, tire pressure, and overall vehicle condition all impact fuel efficiency.
* Driving habits: Aggressive driving significantly reduces MPG.
* Terrain: Driving in mountainous areas or stop-and-go city traffic reduces gas mileage compared to highway driving.
Considering these variables, it's impossible to give a single definitive answer. However, you can expect very poor fuel economy by today's standards. Estimates for a 1981 Suburban typically range from 8-14 MPG in combined city/highway driving, with lower figures being more likely with larger engines and less-than-ideal conditions. Highway driving might offer slightly better results, while city driving would likely be considerably lower.
