2002 GMC Sonoma Poor Fuel Mileage

2002 GMC SONOMA
73,000 MILES • 6 CYL • 4WD • AUTOMATIC
Avatar
NITREX
  • MEMBER
  • 1 POST
I bought this truck 4 months ago and the fuel mileage has gotten worse. The previous owner, who is a good friend got 19-20mpg. I am only getting 14-15mpg. It seems to be poor whether I drive in the city or on long trips. Tire pressure is good, air filter is new. regular oil changes (3000miles) with Mobil 1 synthetic it's whole life. I tried a fuel system cleaner in the last tank of fuel with no change in mileage. Any ideas on where to start?

Thanks
Mar 11, 2010 at 1:46 PM
Advertisement
Avatar
HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
different drivers get different fuel mileage due to the way they drive their vehicles. Do you do fast starts, stop your vehicle with the left foot? these are a few of the things. But get your engine scanned tosee if there are any codes. then have them check the vehicle ofr a blocked/plugged catalytic converter. If you have low vacuum on the engine that may be one thing causing it. the 19-20 range on those vehicles is mostly eway drinving not city. if the truck has different size tires that can effect it as well.
Apr 3, 2010 at 10:41 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.