PDA

View Full Version : 1999 Z71 gets 8.30 mpg is this normal?


David Hartzog
05-23-2007, 11:05 PM
gas is to high to hang on a truck that eats as much as a semi truck and they get 9 mpg.

RossP
05-23-2007, 11:10 PM
i have a 1997 z71 shortbed with 5.0 v8 and it gets around 15 mpg.... you might have a problem:confused:

sooner74
05-23-2007, 11:13 PM
I have a 98 Z71 and I am at 14 mpg, when is the last time you had a tune-up?

David Hartzog
05-23-2007, 11:18 PM
i gets reguler oil changes has new air filter new michilan 10 ply tires new spark plug as of last month new coil new wires fuel filter chanced last year .

cutbetterthanyou
05-23-2007, 11:22 PM
I am going to get a z 71 if you get that good of milage. I have a duramax and only get 9 mpg, and my misto dump gets 11. But i also have a 22ft trailer and 3 zero turns. what do you guys pull?

David Hartzog
05-23-2007, 11:25 PM
i spend $400-$500 a month on fuel for just the truck. i do have a 200 gallon spray...but its not full all the time. the springs on the rear end are compleatly gone...will that matter?

David Hartzog
05-23-2007, 11:27 PM
i have an 18ft with 2 emark, 2 wonder blowers and full tool chest.

toddnks
05-24-2007, 12:51 AM
I had a 1998 Z71 that I loved, and I kept having these strange things happen, and fuel economy would go from like 15 to like 8 from one tank to another. I found that I had a bad gas cap, a plugged fuel filter, and bad O2 sensors.

I don't know if any of that helps, but you should be getting better milage than you are.

topsites
05-24-2007, 01:36 AM
Even with a light foot on the throttle, my '95 D-2500 SLT Laramie 2wd w/ the 360cid gets maybe up to 12...

I would go for either testing or replacing your O2 sensor(s), I assume on a V you have two but it depends on the exhaust system as well, you'll want to check your manual on the procedure(s).

A bad sensor can make a BIG difference, like 20% or so.

And, something else came to mind, just to eliminate the possibility, get a locking gas cap.

KTO Enterprises
05-24-2007, 07:03 AM
Have you done something like have the truck exhaust dualed out and the catalytic converters cut out. That will kill fuel mileage in the truck as the o2 sensors keep getting a lean signal and dump more fuel to compensate. Not only is removing catalytic converters bad for your fuelmileage its illegal :nono:

If you still have the cats in and its not an o2 sensor my guess would be the mass airflow sensor. but thats just a shot in the dark

corey4671
05-24-2007, 07:27 AM
I had a 00 z71 witht he 5.3. I pull an 18ft trailer and 9-10 was all I was getting with it. Dang thing would just scream the whole time pulling that trailer. Moved uo to the 2500HD with the 6.0.....still 9-10 pulling trailer.13 open.

lawnboy dan
05-24-2007, 07:35 AM
true my neighbor cut off his cats and put a huge true dual sys on and his 89 15000 /350 has run like s%&t ever sence. i only gt 10mpg towing with my 2x4 93 1500 /305

KTO Enterprises
05-24-2007, 07:39 AM
And like I said its illegal to remove the cats too. If caught you will recieve a 15,000 fine and possible jail time. I turned 3 people in last year. IF you really want to get down to the brass tacks of it, EPA regs say you must leave he vehicle as factory delivered, no lift kits, no oversize tires, no performance chips, no gear ratio changes. And look for nationwide emission testing in 2008.

ED'S LAWNCARE
05-24-2007, 08:15 AM
And like I said its illegal to remove the cats too. If caught you will recieve a 15,000 fine and possible jail time. I turned 3 people in last year. IF you really want to get down to the brass tacks of it, EPA regs say you must leave he vehicle as factory delivered, no lift kits, no oversize tires, no performance chips, no gear ratio changes. And look for nationwide emission testing in 2008.

Who the heck are you to turn someone in? I would not do it, but I don't give a $hit if someone else does.

KTO Enterprises
05-24-2007, 12:49 PM
[QUOTE=ED'S LAWNCARE;1840274]Who the heck are you to turn someone in? I would not do it, but I don't give a $hit if someone else does.[/QUOT

If you see someone stealing do you turn them in? If you see someone hit a kid with their car and leave the scene of the accident do you turn them in? If you want to live somewhere with air quality like california then get the he11 out of south carolina!

cutbetterthanyou
05-24-2007, 07:15 PM
The exhast is one thing because of air quiaty and noise. What does over sized tires, lift kit, and gear changes have to do with anything. I think you need somthing to do better with your time. Come to Maryland and work for me for free if you are that board.

KTO Enterprises
05-24-2007, 07:24 PM
The exhast is one thing because of air quiaty and noise. What does over sized tires, lift kit, and gear changes have to do with anything. I think you need somthing to do better with your time. Come to Maryland and work for me for free if you are that board.

tire size and gear ratio affect emissions output, Lift kit affects my safety when I drive down the road in my girlfriends VW Beetle. There have been wayyyyyyyyyyy to many fatalities due to a lifted truck literally rolling over a car at a traffic light after they rear ended them. Along with the fact that the components on the truck (brakes, axles, tie rod ends, ball joints) are not designed to handle the load of having to control extra weight of the larger wheels and tires. A lifted truck also has a greater chance of loss of control.

I will say this. Most all aftermarket parts have "For off road use only" on the parts or box. Meaning, car shows, race tracks, nature trails, but not highway. If you hit someone and you have "for off road use" parts on your vehicle get ready to be sued for reckless endangerment and lose everything you ever had or will have.

lawnboy dan
05-24-2007, 09:09 PM
lifted trucks are supposed to be illegal but plenty of bubbas do it anyway

David Hartzog
05-24-2007, 09:38 PM
(Bingo) you're right that exactly what was done.
I plead the 5th.

David Hartzog
05-24-2007, 09:41 PM
Have you done something like have the truck exhaust dualed out and the catalytic converters cut out. That will kill fuel mileage in the truck as the o2 sensors keep getting a lean signal and dump more fuel to compensate. Not only is removing catalytic converters bad for your fuelmileage its illegal :nono:

If you still have the cats in and its not an o2 sensor my guess would be the mass airflow sensor. but thats just a shot in the dark(Bingo) you're right that exactly what was done.
I plead the 5th.

mike lane lawn care
05-24-2007, 10:43 PM
i get pretty bad milage with my 1999 GMC 1500 Z71 4x4, but then again, i have a dual flowmaster exhaust(which by the way is a legal exhaust, and it still has the cats), wider mud tires (again, perfectly legal in MA) and i have a heavy foot. but then aagin, spending hours at a time in the mountain in 4wd, doesn't help it too much either.