Last post on Dec 04, 2011 at 6:52 AM
You are in the Chevrolet Silverado & GMC Sierra
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GMC Sierra 1500HD, Fuel Efficiency (MPG), Truck
#1 of 13 2003 GMC HD 6.0 - Computer settings improve mileage
Feb 09, 2010 (11:10 am)
I just bought an 03 1500 GMC HD with the 6.0l. With 152000 miles, I’m concerned with the 13.2 MPG I’m getting. I was expecting to see 16+ as long as you’re not pulling and keep my foot out of it. What I’d like to know is, I’m going to change the plugs…should I go ahead and change the coils also? I’d like to buy a computer chip but this truck to check setting but I’m not sure what to look for out in the market.
Thanks for your input.
Chris Brooks – newbee.
#2 of 13 Re: 2003 GMC HD 6.0 - Computer settings improve mileage [opc167]
Feb 09, 2010 (11:49 am)
The weight difference between a 1500 and a 1500HD is about 1000 pounds. Your truck weighs a little over 5900 pounds. Because of that 13.2 mpg is about what you're going to get. Changing the plugs may help your mileage depending on the condition of the current ones. I wouldn't change the coils unless you are having problems with the truck.
The 1500HD is the equivalent of the 2500LD which is a 3/4 ton truck. GM had some frame issues back in 2003 where they couldn't make a crew cab off of the 1/2 ton frame dut to cab flex so used as a temporary fix, the 2500LD. Because the gross weight is over 8500 pounds your truck doesn't have an EPA rating.
#3 of 13 Re: 2003 GMC HD 6.0 - Computer settings improve mileage [obyone]
Feb 09, 2010 (11:55 am)
Is this the 300hp 6.0l in this truck?
#4 of 13 Re: 2003 GMC HD 6.0 - Computer settings improve mileage [opc167]
Feb 09, 2010 (12:15 pm)
I've confirmed. It is the 300HP. Disregard my last question.
I appreciate the input.
#5 of 13 Re: 2003 GMC HD 6.0 - Computer settings improve mileage [obyone]
Feb 10, 2010 (4:24 pm)
Hey Dean,this is Howard Villa.Call me let's catch up...7729461...
#6 of 13 2003 gmc sierra 1500hd slt crew cab
May 04, 2010 (4:13 pm)
Engine codes that I was told about was to replace my "throttle body module" computer part mechanic said. I am looking for a better answer either replace the throttle body itself or the mass air flow sensor. My truck is hesitant and I have to really hit the gas to get it going. It is def. not the same power from when I first bought it. Also everytime I start the damn thing it always goes into 4 low and its tough to get out of it sometimes. I have a new alternator, battery, o2 sensors, plugs and wires. Anymore suggestions so I can stop with this money pit??
#7 of 13 Re: 2003 gmc sierra 1500hd slt crew cab [kylegmc2003]
May 05, 2010 (12:07 am)
The hit the gas part reminds me of those Chevies that used to have a binding throttle body due to carbon buildup on the linkage or the throttle plate. Try check to see if either has a buildup or if the throttle plate linkage is bent.
#8 of 13 bad mpg with my 2006 gmc
Jun 30, 2010 (5:17 pm)
anybody have some ideas how i can get better mpg with my 2006 gmc 4x4 truck with a 5.3 gas engine. my truck has 39000 miles and gets 12 mpg
#9 of 13 1500 hd won't start the first time
Aug 25, 2010 (8:02 pm)
How's it going everyone?
I need some help with a problem I have had for a few months now. I have a 2003 GMC Sierra 1500hd 6.0L pick up with 86,000 miles and it will not start the first turn over. If I then proceed to try again it will start either the second or the third time. If I have driven it recently it usually starts up the first time. I replaced the fuel pressure regulator and that did not help the problem. I noticed if I turn the key from the on and off position quickly 5 or so times, it starts right away. It seems I am not getting the fuel into the motor right away, is this the fuel pump? Fuel filter?
Any help would be appreciated.
#10 of 13 2010 1500 slt Z71 4x4 5.3 engine
Oct 31, 2010 (9:40 pm)
I have a 2010 GMC Sierra Crew Cab 1500 pickup with a 6 speed transmission. The transmission has selections for Park, Reverse, Neutral, Drive and (M) M allows you to select from all 6 speeds. 6, 5, 4, 3, 2, & 1. You can use Drive only or move the gearshift into (M) that should first go to 6th gear at top so the transmission does not tear itself apart by dropping down into a much lower gear such as Low (1). Well my problem is when I select (M) it first shifts down into Low (1) which could destroy the tranny and who knows what else. Has anyone who owns the 2010 (or other years) GMC Sierra 1500 pickup had this happen?
Help me please. CAH
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