The dealership puts the cheapest oil they can put in it from the factory...lol I have been running 5W30 regular oil NOT synthetic since I purchased my 04 GMC Sierra. I change the oil every 5K. I normally just buy whatever the autoparts store has on sale or lately I have been running Wally World's Tech 2000. And I change the filter everytime too. Filters I just buy STP normally or the Tech 2000 filter. I have not had a problem yet. I normally use a half a quart of oil between changes. However I did use Quacker State 1 time and it used 1 and a half quarts of oil between changes. Since then I have never used that brand oil again and have had no problems. Oh and I have a 105K miles on the engine now average.
Now my buddy uses Caster (Castro) Oil. He went from 5W30 to 10W40 at a 100K and then 20W50 at 150K and has had no problems. Now back to the original topic of this thread... my buddy averages 16 MPG since he has owned his 01 Chevy Silverado with the 5.3. And he dogs that truck. He is a speed freak and is a Volunteer Fireman too... self expained right? lol He is the only one I have not seen his MPG increase since he has owned the truck. Everyone else's MPG ahs increased over time.

 

i have a silverado 2010 4.3 1500 reg cab, i now have 7000 miles on this truck and i am very unhappy about the mpg, this thing is rated at 20 mpg city and 28 mpg highway, now i know these ratings mean only so much but i am getting 12 to 13 mpg city, about 16 mpg med speed city driving and about 22 mpg highway, very minimal increase since new, had it in to the dealer yesterday and they did a diagnostic and looked for software updates for fuel economy which there were none and have no idea why my mileage is so poor even admitting it should be better....thinking of putting in a throttle body spacer and k&n flow system, one dealer told me i can,t do this it could void warranty and this dealer told me i could do it no prob so have to find out for sure.....put in these products plus flow master on my 98 chev 5.0 and 98 gmc 4.3 and it made noticable dif in power and mpg.....any thoughts on doing this to my 2010

 

I was always told the same thing no matter what car i bought, "give it some time and it will improve" My 05 Silverado from day 1 gets 16mpg no matter where i drive it, city or highway. I had an explorer the window sticker said 23 high way. I put 140k on it and no matter how i drove it it only got 18mpg from day 1. My opinion it wont improve and if it you see an imrovement its probaly related to your foot being lighter on the gas. At least the chevy gets better mpg than the ford and dodge pickups.

 

Different car, but my grandparents bought the new Terrain which is advertised at 34mpg. They drove it to Florida (from michigan) in Eco mode, and returned 18mpg.

My GM retiree grandfather is now looking at a BMW

 

2010 5.3L Crew Cab Z71 7000 miles. Drive highway every day - 25 miles each way - get 17.1-17.3 MPG every time. Best I've seen was 18 on Interstate for full tank.

 

I know its cliche and everybody says it, but keeping the reccommended tire pressure (or slightly above) makes a difference of one or two mpg. Especially with the cooler weather coming in (depending where you are). I like to use Lucas Oil's fuel treatment additive too. I get about 22 in my stock 06 silverado.

 

2007 4x4 4.11 6.0 extendacab installed a superchip from my son and went from 16.7 per 100kms driving 120@2400 to 12.0 per 100kms at 10@ 2000 took the chip out and gave it back to my son who has sme truck and year with engine but with 3.73 and he gets 12.0 per 100kms at 120mp tghe chip does work but now i think the taller tires will reduce rpm at same speed,i still use 93 octane but chip was set at 87 octane..the truck is really scary when set on performance byut best milage was on 87 octane

 

i have a 2007 4x4 extendacab 4.11 6.0 ,son has same everthing but 3.73 gears he gets 12. lts per100 at 110 1900 rpm appr. used his superchip and tried it out on my truck ,drove ottawa to dundee mi trough us and then back through canada,1728 miles. left the chip on performance, quite impressive 16.7 lts at 110 anything over just sucks her down.put setting on 87 octane and drove at 100-105 and got 12. per 100 lts all we both use is 93 octane..in canada it takes 4.5 lts to make a gallon of gas but to compare fuel it takes 5 us gallons to make 4 canadian gallons , maybe i am only getting 16-17 pet us gallon but it gets same when we haul car haulers for moose hunting to the manitoba border every year we only drive 50-55 at this time keeping the rpm down is the answer and milage is good

 

i have a 2007 4x4 extendacab 4.11 6.0 ,son has same everthing but 3.73 gears he gets 12. lts per100 at 110 1900 rpm appr. used his superchip and tried it out on my truck ,drove ottawa to dundee mi trough us and then back through canada,1728 miles. left the chip on performance, quite impressive 16.7 lts at 110 anything over just sucks her down.put setting on 87 octane and drove at 100-105 and got 12. per 100 lts all we both use is 93 octane..in canada it takes 4.5 lts to make a gallon of gas but to compare fuel it takes 5 us gallons to make 4 canadian gallons , maybe i am only getting 16-17 pet us gallon but it gets same when we haul car haulers for moose hunting to the manitoba border every year we only drive 50-55 at this time keeping the rpm down is the answer and milage is good all i know is that when we fill up the hemi,s take more fuel loaded or empty