I have a stock 2006 Chevy Silverado Crew Cab with about 18,500 miles on it. I am a careful driver. Don't accelerate hard and try to drive very economically.

My average mileage (I keep extraordinary records) over the 18,500 miles is 17.65. Highest I ever got on a trip was 21.15. Lowest I ever got on a tank (mostly in town driving) was 13.6.

I have a Laredo vinyl bed cover. All tires are stock and I usually keep them at 35psi or so.

I've heard people talk about increasing gas mileage with either the K&N paper filter replacement elements OR the K&N cold air intake.

I have no need of more torque or horsepower. I don't pull a trailer and use the truck to carry things hOme from Lowes or Home Depot.

I pretty much do everything recommended to optimize my gas mileage.

Would any of the K&N products or any other cost effective mods make a significant increase in my gas mileage?

thanks for any feedback you can offer.

Mike in Alabama

 

This worked for me, but I like to "tinker" with stuff so its up to you.

Get a K&N air filter for starters. Yes they work. Then get a cooler temperature thermostat, say 180 degree. (Therostat is optional but they work well) Now you can either get a tune or a programmer and they work well too.

This is what I did:

Got a Predator programmer and with help form Diablosport I managed to dial in a few parameters to help the truck run efficienty.
1. Adjusted Long Term Fuel Trims and Spark Advance
2. Adjusted transmission shift points and pressures
3. Removed 60% of the torque management
4. I also played with WOT parameters but that was for play not fuel effeciency.

So what this did is allow the PCM to compensate for the added air coming into the engine via my Cold Air Intake (Better air to fuel ratio) Then I bumped up the low RMP fuel trim and increased the spark slightly. (More low end power to keep the rpms down when cruzing) I also adjusted the transmission shift points (I made the truck hold gear longer so it would not down shift nearly as much as it did before). Along with easy driving I got another 1.5 mpg out of my truck on average (combined highway and city driving). I have to double check my most recent mpgs but I went from 16.5 on average to 18 in the winter, now that the weather is better I might have gotten a little more.

 

yeah i have the k&n cold air intake and it gave me about 1.5-2 mpg in the city (if u drive it right) and boosted me to about 22.6 on the highway. thats the highest ive gotten on a trip so far with temperature being in the mid 60s.
although, i do have a magnaflow dual exhaust system. however, if your truck is completely stock and you add on a k&n filter or wanna go with the full intake, you'll see about a 1.5-2mpg gain. when i got the dual exhaust my mpg went down, but, then again, i need a tuneup, and a tune.
overall, k&n intake is the way to go, it just all depends on whether or not u wanna spend 50 bucks on a filter, or 200 on a CAI

 

Boss I would love to have a truck with only 18K, you are a lucky man.

Note to wise: I would not do anything to that truck until you check with your dealer, they will be looking for any mods you made if you bring it in with major problems.

Increase mpg:

k&n air filter or other like type filter
synthetic oil in all drive train systems
tires inflated 3-4 psi over std rating

for every 5 mph you drive over 55 mph, you drop about 1 mpg.
take off and stop like an old grey beard like me.

I am driving a 2000 model obs with 350 engine and 3.73 gears. My truck is looking for a gas station all the time.
about 13-14 in town and 15 with a tail wind on road, but the old boy can and will pull when hooked up.

However, I will be paying dearly for that when gas hits $4

 

suggestion: dont dual out your exaust system if u are looking for increased mpg. Ive found that due to loss of back pressure that it rapes your gas milage, but somewhat increases your power. I think a simple cat-back system would boost your mpg while gaining some power and great sound as well.

 

You can have duals and an intake and all that and yes it will effect your mpg, but until you tune or program that truck it will not get the best mpg! Trust me! I have been screwing with mine for months now and every time I do I get more out of a tank of gas. Its all about getting the best AFR and Long Term Fuel Trims. After that you have to program the transmission for your driving style. After all you can only squeeze so much mpgs out of a V8, now the rest of the gains need to be from the transmission. Make that engine work for you without going into the higher rpms!

Every mod done to that engine will change the AFR and LTFTs. So having someone dyno tune or program then back to normal (or better than normal) is the best way to get mpgs and hp. When an intake and TBS is added (depending on the manufacturer of either) you can lean out the engine because there is more air coming into the engine than what the truck was programmed for. This causes the timing to back off, the hp to drop to stock or less than stock, and therefore kill your mpgs. Same goes for the exhaust, low rpms get less hp with freeflowing exhaust, but a tune can put it back to normal or better.

I need to clock my mpgs on the highway, I have to be getting 22 or better. I can cruize it on the hilly turnpike at 75, merge, pass, etc...and never downshift once! And I have the weaker of all the 5.3s.

 

Thanks to all. I'm really trying to find some mods that will have a pretty quick payback. If the CAI is $200.00 and I add say 1.5 MPG over my present average (17.65 to 19.15) driving 10,000 miles per year; the payback would be a little over 15 months with gas at $3.50/gal.. Would I see much difference replacing my present pleated air filter element with the K&N pleated element? I'm not sure I want to do any big mods to truck until it's out of warranty.

As to oil, I've always been a dino oil man as I've religiously changed my oil every 3,000 miles. Always used Castrol GTX. Never had an engine failure or problem. I've always been skeptical of people that use synthetics saying they go 10,000-15,000 miles between oil changes. Since I do change oil every 3K, I wouldn't likely save enough on gas to justify the higher price of synthetics if I keep the 3K interval. I might if I didn't change oil but every 10K but I'm leery of that approach.

Stock tires I keep at 35. Is running them at 38-39 cold pressure OK?

You guys are great. I love my truck but it's been an adjustment for sure getting used to the gas mileage!

Mike in Alabama

 

I use synthetic oil but I would NEVER go over 3K on oil no matter what. Those people who do that are nuts!

Your best bet would be a K&N air filter and a lower temp themo stat. Exhaust will kill low end power unless you get a tune. The K&N will increase AFR without leaning it out, and the lower temp thermostat will increase low end hp and torque allowing you to stay a little more out of the higher rpms therefore saving on gas when driving normally. The lower stat will also help prevent any leaning out probelms in hot weather.

Now if you feel the need to blow $200-$300 on a tune or programmer, then you can do the complete CAI and exhaust and "dail it in" to gain more mpgs and hp. Not too bad of an investment if you drive alot on the highway. But it will take awhile to gain that money back in fuel savings.

No matter what keep the TB and MAF clean and run some injector cleaner every now and again.

 

Thanks to all. I'll look at the t-stat chnage to 180 but i would almost swear that my mileage is worse in the winter than in the warmer months even after the car is fully warmed up. Maybe my imagination.

As to the K&N, I'll give it a look.

Few more questions. The truck has 18K and the only maintenance I've done is change oil and filter and rotate tires. I haven't changed the air filter as the green/red spring loaded indicator still reads OK. Is it still best to ignore that and change air filter every 12K. If so I'll get the K&N pleated filter for mine now and replace. Is there a fuel filter to be replaced periodically as well?

What do you recommend and how to clean TB and MAF and what is a good brand of injector cleaner? I've used Techron before but does that adequately clean injectors?

Thanks so much,

Mike

 

your mpg would be slightly worse with a lower temp thermostat. it runs the engine colder so the engine needs more fuel. throttle response and power will seem to be better but that is becuase the engine is getting more fuel. i would just leave the thermostat alone.
i would kill for 17mpg like you are getting. with the truck stock i got about 12mpg. with my mods im lucky if i break 14mpg.