Last post on Mar 27, 2013 at 11:39 AM
You are in the Chevrolet Silverado & GMC Sierra
What is this discussion about?
Chevrolet Silverado 1500, Chevrolet Silverado 2500, Chevrolet Silverado 3500, GMC Sierra 1500, GMC Sierra 2500, GMC Sierra 3500, Fuel Efficiency (MPG), Truck
#155 of 176 Re: 2011 Silverado 5.3 Crew cab 3.42 rear end Low MPG [cabe227]
Feb 19, 2012 (9:04 am)
Doesn't that really hack you off! No, I haven't found the problem yet. And since there is no trouble code, I'm stuck. I've been considering getting an aftermarket program fix, but I keep hoping it might correct itself, but I'm pretty sure that's not going to happen.
I prepared a letter earlier this month, outlining all the poor gas mileage & Active Fuel Management problems i'm having with my truck and sent it CERTIFIED Mail to BILL SUESSMAN, who is the General Manager of Ron Craft Chevrolet in Baytown, Texas. I've gotten no response. He has ignored my letter.
Please let me know if your programmer worked for you! My overall mileage right now shows 14.7 MPG. I drive about 60% at 60 - 70 MPH. MY Active Fuel Management system rarely works at that speed, except when going down hill.
Someone else may have previously found out what the fix is to this problem and will respond on this post, I hope
Feb 19, 2012 (2:10 pm)
I reset my average MPG meter and drove about 100 miles 15 in town the rest on a 55 MPH highway. running E85 I'm only getting 10.7MPG. I'm planning a trip to the east coast (~1000 miles) and plan on switching to 87 or 89 octane. I hope the superchips Cortex computer can help me get atleast 15 MPG. Im thinking that our trucks are just a bad batch and there isnt enough of them out there for a recall. With the 3.42 gearing and 6-speed transmission and the 5.3 motor we should be getting 18 or better. My 2005 GMC had 4.10 gears and a 5 speed OD tranny with the 5.3 and it got 18+ hwy with 33" tires. Anyway, the computer will be here this week so ill be sure to post results, E 85 and 87-91
#157 of 176 Re: 10.5 [cabe227]
Feb 19, 2012 (2:34 pm)
E85 will net you lower mpg. I get 12 to 14 on 87 around town. So the 10ish on E85 doesn't sound outlandish.
#158 of 176 Re: 2002 silverado Z71 ext 5.3 with 3.73
Feb 20, 2012 (7:40 am)
If it helps. I have an 02 Z71 with the 5.3 and 3.73s. It has 79000 miles on it. I drive it 25 miles to work w/8 trafic lights and 3 stop signs. I upgraded the truck with a K&N system and a Flow Master cat back. I get 17-18 mpg around town and 18-19 mpg on highway (w/east coast hills). I have found it gives me a lot more bottom end power also. Big key I have found over the years is More air in and out helps alot. Gota let the truck breath.
#159 of 176 Re: 2002 silverado Z71 ext 5.3 with 3.73 [jcmoore2]
Feb 20, 2012 (11:27 am)
Does the K&N System have anything to do with changing the computer programming that might void the warranty? Is this system one that you order and put on yourself or is it something you need to have installed?
What kind of gas mileage were you getting before you upgraded to the K&N system?
#160 of 176 04 silverado 5.3 MPG 4x4
Mar 02, 2012 (9:17 am)
Come on guys, all you silverado owners need to quit lying to yourselfs. I accepted & came to terms with the mpg my Truck gets. Here's the figures driving it like theres an ege between the gas pedal & the floor. 11 city 16 hwy at 70 mph. This is horrific! I thought something was wrong till I talked to a Co. worker that had same truck. SAME MPG numbers. And dont go by that dumb computer on the dash. Chevy just put that there to make us feel better. Calculate at the pump. "miles driven divided by gallons of gas used". Only way to get tru figures. Im going back to my 86 toyota 4 banger. Never let me down and get 23 on the hwy all day long, and is a lot funner & easier to work on. And can actually hold its own off road. Accept what you get, you'll feel better after. Id sell while you still can before gas goes up anymore. Mines worth less than half of what I paid for it after only 55,000 miles. Just my 2 cents worth guys.
#161 of 176 Re: 04 silverado 5.3 MPG 4x4 [soleri]
Mar 08, 2012 (4:50 pm)
"16 hwy at 70 mph"
This is much less than others. Couple of questions-
Did you add bigger tires?
Do you have a lift?
Do you have a CAI?
#162 of 176 Re: 2002 silverado Z71 ext 5.3 with 3.73 [string2]
Mar 09, 2012 (5:08 am)
Hi String, I have a GMC sierra 2003, SLT, 17 in Denali take offs wheels, 32.5 Yokohama ( M&S), "NO LIFT" ...I run mobile 1 synth in tranny, and diffs (expensive tranny fluid). I have a KN FIPK, and stock exhaust, I have a 300# bed cover-fiber glass and painted. Tire pressure I maintain about 35# every tire. My best all around mileage is about 17.9, ....if I spend 80% on highway .. usually around 18.7mpg for longer trips ( 60-75mph). If I keep it near 65 mileage goes to 20-21.... this is in the northeast and tons of hills. Long drives on back roads ..no lights or stop signs upper NY ...im 21MPG,
I also installed an electric fan ( and took the crank shaft weight off motor) FLEXLITE - engine seems much happier starts easier runs smother.. and punch is great at rear wheels.. i have heard 10 % low end HP but have yet to measure rear wheel HP
exclusively city I'm about 14.5 like jersey city
#163 of 176 Re: 2002 silverado Z71 ext 5.3 with 3.73 [ttaupier1]
Mar 09, 2012 (8:33 pm)
When I first posted to you, I didn't notice that your model engine doesn't have Active Fuel Management. But it looks like you are getting mileage as good or better than most with AFM. I'm running a stock 5.3 2011 Silverado Crew cab, 3.42 dif, tires pressure 35 lbs, - 6,300 miles. My average city is about what I expected, about 14.7. However, my average highway mileage is about 16 MPG (almost all level highway). My AFM is not working above about 60 MPH. GM says they would fix it, but they can't get the truck to produce a trouble code to show them what to repair. Otherwise, they say, they have to assume it is working as designed. Do you have any ideas that will get better mileage out of this engine that won't void the rest of my warranty.
#164 of 176 2001 Chevy Silverado Superduty
Mar 13, 2012 (3:50 am)
I bought a 2001 Chevy Silverado Superduty dually last year to pull our 14,000 lb fifth wheel. My husband says it only gets 2 miles to the gallon while towing (gas not diesel) Is there ANY way to improve this performance? It's really hard to imagine any vehicle that only gets 2 miles to the gallon.. But this silverado never misses the opportunity to stop at a gas station. We have an upcoming 900 mile trip one way towing the 5th wheel so I'm looking for some way to maximize the gasoline consumption since prices are entering the stratosphere on gas now.
Any help appreciated.