'01 GMC Sierra 1500 is worthless

[Christ]

I know the 4.3 5 speed GMC trucks could do 20 without too much pissing and moaning... I dunno about yours, though. And mine had P-type tires on it, not LT's.

[rmay635703]

My 350 Gas 1993 Suburban historically got around 18-20mpg on the highway and about the same in town if you screw around a lot. Near the end I was getting around 24mpg on the highway loaded down with a generator off the back just by letting the thing slow down and speed up, sweet spot was around 70mph but not going up the hill.

My suburban has slightly better aero than your truck but not much, I should think it possible to get better than you are doing, someone should figure out why 93's always got better than the 92 and 96 year suburbans. Gearing, computer, transmission, not sure. I do know in town you have to accerate quick and coast a lot, suido pulse and glide helps.

Also I have been able to coax 20mpg in both in town and highway driving out of my auto dodge ram 1500 crewcab 318 V8, I found that shift to neutral dropped fuel consumption instantly down to the idle level and the truck coasts well. But I got a check engine light after doing that a lot about massive vacuum leak, went away after that without coming back.

Autos CAN be hypermiled but each one is different and you need to do things that are NOT intiutive to coax them into performing, my buick is that way, I found that I have to let off the gas periodically on the highway to keep the FE high because the car's MPG starts to lower after a while of steady state, I then have to wait for the GPH to drop (its like it gets stuck at .75gph when I let off the gas), Anyway let off the gas, wait and push the pedal back in and FE goes back up, strange.

Cheers
Ryan

[wriley4409]

I own a 2007 "Classic", with the 4.8 liter engine. The things that have made a difference to me are:

1. higher tire pressure
2. using a scangauge to get a feel for how to change my driving habits
3. gm switched to pure synthetic oil in the differentials in '06, so you might try that
4. gm switched to electric cooling fans between your truck and mine - try that
5. using a tuner to lower engine idle speed makes a difference
6. using low rolling resistance tires (not LT rated mudders) makes a 1-2 mpg difference
7. lowering your truck would make a difference

[pgfpro]

Originally Posted by wriley4409

I own a 2007 "Classic", with the 4.8 liter engine. The things that have made a difference to me are:

1. higher tire pressure
2. using a scangauge to get a feel for how to change my driving habits
3. gm switched to pure synthetic oil in the differentials in '06, so you might try that
4. gm switched to electric cooling fans between your truck and mine - try that
5. using a tuner to lower engine idle speed makes a difference
6. using low rolling resistance tires (not LT rated mudders) makes a 1-2 mpg difference
7. lowering your truck would make a difference

I'm going to look into a electric fan. I know when its really cold or hot the fan sounds like it needs to be attach to a airplane.LOL

[The Atomic Ass]

Originally Posted by pgfpro

This thing is a fuel hungry monster. I have tried all the easy mods and have had no luck

I can drive this thing like a "Bat out of Hell" or like a grandma going to church and it gets the exact same mileage.

Well, yeah, that's the way it's designed. That's the price to pay for buying from a company that's in bed with the oil companies.

On a serious note, it's extremely difficult to get any better with GM's large-displacement, slush-boxed trucks. It can be done, but it's still tough.

[The Atomic Ass]

Originally Posted by pgfpro

I haven't done a whole lot, just the low $$ mods.

Canopy
Tire pressure increase to 50psi
Driving techniques
Driving with out A/C with windows up
premium fuel

The next thing I'm going to try is a non-ethanol fuel.

Non-ethanol is good, lose the premium. Run the lowest octane you can find, assuming it's a 2-valve motor.

[The Atomic Ass]

Originally Posted by pgfpro

But the dang thing pings all the time when I'm on the on ramp so I decied what the heck i'll try a higher grade fuel.

But does the Check Engine light come on? The computer will retard ignition timing to avoid detonation, so unless something is seriously amiss with that engine, you're probably hearing something else. Radiator fan just tickling the shroud perhaps?

[The Atomic Ass]

Originally Posted by Christ

Try unplugging the knock sensor for a trip, see if you can get it to drive normally without pinging without the ECM getting involved.

I would think that would throw a code and kill timing, power and economy.

Just a guess based on my knowledge of how the ECM works.

[darcane]

Originally Posted by The Atomic Ass

Well, yeah, that's the way it's designed. That's the price to pay for buying from a company that's in bed with the oil companies.

On a serious note, it's extremely difficult to get any better with GM's large-displacement, slush-boxed trucks. It can be done, but it's still tough.

You've got your little smilie up there... but I see this sort of thing a lot about GM trucks. I just don't understand why.

I needed a full size truck that can seat my whole family and tow a decent sized trailer. That meant a V8 and an extended cab, full size truck. Go over to fueleconomy.gov - advanced search and limit your search to 2001 2wd gas pickups with 6-8 cylinders and an auto. What's the first you see with a V8? GM...

You can do this with most years and see GM or Ford as the first on the list. A major reason I picked a Chevy because it was the most efficient truck in the class I was looking for.

-Mike

[rmay635703]

Originally Posted by darcane

You've got your little smilie up there... but I see this sort of thing a lot about GM trucks. I just don't understand why.

Simple reason, GM was ahead of everyone else and owned the rights to a then and now revolutionary battery. They turned around and sold the rights to their breakthrough battery for peanuts to Cobasys a Chevron holding company. I can't think of any logical reason they wouldn't want to profit from the patent?

Originally Posted by darcane

I needed a full size truck that can seat my whole family and tow a decent sized trailer. That meant a V8 and an extended cab, full size truck. Go over to fueleconomy.gov - advanced search and limit your search to 2001 2wd gas pickups with 6-8 cylinders and an auto. What's the first you see with a V8? GM...

You can do this with most years and see GM or Ford as the first on the list. A major reason I picked a Chevy because it was the most efficient truck in the class I was looking for.

-Mike

I agree with what you posted, GMs big boys always have done better than ford or dodge. I just wish more people would buy manual transmissions so I could end up with one some day.

I myself have always driven GM suburbans loaded up for doing craft shows and I have always done well comparitively speaking on FE. Why did I have a suburban? Because it gets better FE than a van but still works as a van.

I can't figure out why no one believes a old Suburban can get 20mpg? let alone 24mpg when I finally pulled my head out of my ...

Cheers
Ryan