Gmags

I have a 2005 Silverado crew cab, 5.3 with 3.42 gears and LT 285/70R17 tires. My average Mpg is 15 - 17 on the highway. I recently installed a K&N airintake systemto work with my fiberglass ram air hood and have purchased a Hypertech programmer. Currently working with the programmer to see if it helps the mileage.

Looking forinfo for better mileage (besides driving habits). I have read posts claiming 21, 22 and even 27 Mpg and can't believe it.

old dog

wishful thinking with a fulsize truck !!!!!!!!

Gmags

Yes, I agree, Over 20 miles to the gallon in a full sized truck with oversized tires seems odd, but there are claims.
Also wondering how much of an improvement a throttle body spacer would have on Mpg.

old dog

i guess you could try it if they will guarantee you money back if no significant increase ,90 percent of those are smoke and mirrors .if it sound's to good to be true ,it probably is .i got suckered in 1 time on a tornado ,did not work ,made them give my money back.i keep impeccable mileage record's and am a conservative driver .

therewolf

Not to be disagreeable, but I switched to 342 gears, got a K&N CAI, and my 04-2500HD- 4x4-6.0L crewcab longbed is now getting 18MPG prior to programming and ignition mods. I drive conservatively, and have a Century fiberglass cap on my bed.

While I am still on a grailquest for the elusive 23MPG, which would be exactly double my factory MPG rating, I feel sorry for all those poor schmoes out there who have been duped by manufacturers into thinking if you want good mileage you have to drive some pokey little half-a-car the size of a wheelbarrow.

I certainly hope there is an improved mileage perfomance in my future, and I find claims in the 20-30MPG range to be conservative enough to be encouraging. If my lumbering beast can get the MPG it gets now with no internal engine mods,and changes simple enough for the backyard mechanic, I truly feel there is hope for us all.

Gmags

So, 18 Mpg before engine mods, what are you getting after engine mods andwhat kind of mods are you talking about, ECM chip or installed parts?
If you can achieve 18 mpg with a6.0 hog, I should be getting 20 plus with my 5.3, and it's not happening. I would like to know your secret.

therewolf

For starters, 80PSI E-rated Radial Tires. Those 285 tires are killing you, stay with the factory 245 width and watch that mileage climb.

Your picture shows two hot trucks, but it's too small to clearly see the beds. Do you have a cover on your bed? It cuts down air resistance. My fiberglass bed cap gave me a whopping 3.5MPG all by itself.

A good wash and wax job helps, believe it or not.

Currently, I'm experimenting with a programmer. In the future, mods may be MSD ignition,HHO fuel additive/management,and possibly a more efficient intake manifold,(although I'm not sure if one is currently available)a narrow set of headers(for cooling & flow)and possibly a dual exhaust.

Attitude,attitude,attitude-not just "don't run & gun", glide when you can, cruise control can save you a fortune in areas without hills to climb.Look as far ahead as you can to figure out as far in advance as possible when you'll have to stop, and coast to a stop slowly, try to outwait the light, it takes a lot less gas to roll away from an intersection than start all over again from zero. Always ask"Do I really need to pass/change lanes?". On a long trip, pick a lane, pick a speed, set the cruise control, and try to stick with it.

Keep in mind that a lot of increased mileage is hard won. Not a lot of gains are going to be dramatic,(although changing back to 342 gears gave me back almost 3MPG highway and doubled my mileage around town)most will be less than 1.0 MPG, but they all add up!

After your tire change and you cover your bed, I fully expect you to message me back telling me you're exceeding 20MPG. I should be by then! Best of luck.

cams 98 silverado

i gotta say, i know im young. im that one that will have the music up and ill be cruisin down the road a wee fast. but some thought to your fuel quest. I live in illinois. and by me theres a speedway, mobil, route 66, and shell. oh cant forget thorntons. i have filled my tank from about the same spot to top full. adn i drove the same way through out the tanks. my finding for my vehicle and might i say i drove like a good person. nice and easy but not like the granny in the full size buick. through all that gas i found that speedway is much better for my vehicle. i got almost half the miles from the thorntons tank and shell was alright. the worst though was thornton then mobil then shell then 66 then speeday. speedway being the top. have you ever thought about that? and also. i got that great job of working at a lovely jiffy lube and while working there i have done more thinking. fuel filters. do you change them when needed? i went 90000 miles on the origional filter and well personally was shocked when i saw clear gas flowing out of it. when you take off an old filter you close both ends, shake it and pur out the gas. usually it comes out dirty rust looking and dark. mine came out clear. and yes i know for sure it was the origional filter. there was all those tags from the factory saying this is tested blah blah blah. thats just another thing to ponder and calculate into your already very good ideas. personally. all those who have kept their truck and still drive it and pay teh gas bill are true truck owners. now i know there are some who need the truck. those are true owners as well but the ones who bought the truck thinking " man, that is one sick engine but to get the old lady to agree ill tell her what if... we move or need big things that wont fit in a can or dinky car," ARE TRUE OWNERS. just my two cents.

therewolf

Here's something you can calculate about gas filters-there is none for my truck! I even went to the dealership where I bought it and asked for one after a thorough intake-to-gas tank search. They replied at the parts counter "There is no gas filter for your vehicle."

I believe there is some truth to the "gas quality" claim of Cams98, but until we find out if it's freshness,octane,purity(my guess) or some other "x factor" influencing the quality of the fuel, we'll just have to fill up at the gas station we like best, without ever really knowing why. I think Gmag's original post concerned things we can knowingly do and control.

One thing I neglected to mention before in my previous post is you have to be obsessive about vehicle maintenance. Sorry, Iridium plugs, in my experience, are only good for 50,000 miles, which by most standards ain't bad, but it's half what GM claims. And you have to, as in MUST use Iridium AC/Delco replacements or you take a great risk. A good set of FIRM Gas Shocks will also give you @.3MPG, just remember when it's time to replace the originals that good quality shocks will pay you back at the pump. Clean the grease and glop off your skid plates; and paint them when you replace your steering damper. Tighter steering= better gas mileage. Better airflow over your skidplates = better gas mileage. Tire inflation-did you know you lose about 5 PSI per month? That's a couple MPG plus or minus, depending on if you remembered to "air up" regularly. It all slowly adds up to significantly improved mileage.

A side benefit to all this effort is that you will have a truck with superior handling, which is cleaner, and with which you will be much happier overall.

Gmags

Enjoyed reading your comments Rivereye. You brought up somegood points.
First off, thanks for noticing. Both trucks are hot. Red is a 1990 1/2 ton with a fiberglass fastback and the Gold is a 2005 1/2 toncrew cab. Red is the work truck and the gold one is for travelling. Both have toneau(spelling) covers for mileage and both have oversized tires. The 1990 has a 5.7 and only gets 12 mpg, not worried about that cause it's a work truck, it's the 5.3 that should be getting better than 18 mpg.
I would like to comment about the tire pressures. Have you ever thought about nitrogen in the tires? I am being told that the pressures will stay stable a lot longer.

I have been thinking about changing my plugs and wires, I have almost 58,000 miles on the original/factory plugs and wires. Any suggestions? I will be looking for a quality product.

I am still looking for info on what I can do with my programmer as far as shifts areconcerned. The instructions are not clear when askedif I want tochange the RPM of the shift points.