2001 5.3L gas mileage/power

[Obi-Wan]

We bought a 2001 Tahoe (5.3L, 4x4, 3.73 gears, 63K miles) back in January. It's primarily my wife's daily driver, but it's also our family vacation-mobile and occasionally a tow rig for my 3500-lb Jeep. This is mostly below 2000' elevation, but with occasional trips to the mountains of Colorado. It's bone stock so far.

We've been getting about 11 mpg around town and about 14-15 on the highway (unloaded). Towing the Jeep through hilly terrain at 65-70 mph, it also got 11 mpg. Is this typical gas mileage for this truck, or is it low? What do the rest of you get?

I've also noticed recently that when driving at 65-80 mph (interstate), it has to drop down out of overdrive more than I'd expect it to in order to maintain speed up hills.

Without spending huge amounts of money, I'd like to both improve the mileage some (if possible) and increase power enough to stay in overdrive on hills.

Any suggestions? Do the no-name cold air intake kits on eBay (like item 2474841636) do much good below 2500 rpm? Would a K&N FIPK work any better? I think a new exhaust is off limits (wife's truck -- I have my own toys). I'm gonna do my first round of general checkup & maintenance soon, since we're planning a long road trip next month. It'd be nice if I could boost the mileage before then.

[PowDuck]

My first response (since I've just had this experience) is to change your fuel filter. My 2000 Tahoe, same setup as yours except with the 5.7L was getting 17.8mpg hiway and 14.6mpg city when I got it with 42K miles. >>>---- Long story short ----> I put injector cleaner in the tank and my mileage went to 13 and 11. Changed filter and back up to 13city and 16 hiway (larger tires now, too).

[Obi-Wan]

Originally Posted by PowDuck

My first response (since I've just had this experience) is to change your fuel filter. I put injector cleaner in the tank and my mileage went to 13 and 11. Changed filter and back up to 13city and 16 hiway (larger tires now, too).

I recently added injector cleaner to the tank, too. Where is the fuel filter on this truck?

[gurrzt]

look under the truck and follow the fuel line out of the tank, it will be attached to the frame, near the gas tank, it should be a round metal canister.

[sgeorge]

My 03 Tahoe 5.3l Engine Gets 21.5 With The Cruise On. Average Without 19mpg. No I Am Not A Slow Poke. I Installed A K&n Air Filter And I Use Only Full Synethic Oil.

[djmann02]

I would suggest going to some 3.42 gears. That engine will have enough torque where you won't need the 3.73's. They are keeping your RPM's too high. Are you using or having to use your 4 wheel drive for any of the listed applications? Don't if you can help it. And, on the air intake thing, I have heard and read great things on the AIRAID intake but it will set you back about $200. You might want to check into the Hypertech computer programmer also. I had one with a previous vehicle and they are wonderful. You would need one anyways if you changed gear ratio in order to calibrate your speedometer.

[Obi-Wan]

OK, here's an update. Here's what I've done to the Tahoe in the last month: New fuel filter, new K&N oil filter, changed oil with Mobil 1 synth, new K&N stock-style air filter, new Autolite platinum plugs, cleaned carbon with SeaFoam. We then drove on a 1500-mile road trip, 300 of which was inside the Dallas metro area (lots of urban highways).

Before the upgrades, we'd gotten about 15 mpg on the highway and 11 mpg in town. During the trip, we experimented with different fuel octanes. On the way out, we got 16.5 mpg (89 octane, 10% ethanol) and 15.5 mpg (87 octane). Much of this trip had a strong head wind. On the return trip, we got 17.5 mpg running 91 and 93 octane with an occasional strong tail wind. Within Dallas, we got 13.7 mpg on 93 octane. Pretty much all of the rural driving was done around 70-75 mph with cruise control on reasonably flat highways. I haven't yet used a full tank around town since we returned.

Obviously, the Tahoe doesn't like 87 octane. I think anything over 89 octane is probably a wash, though. The K&N air filter was probably good for about 1-2 mpg. Everything except that & the SeaFoam was done a couple weeks before our trip, and didn't seem to make much difference.

I opted to get the stock-style K&N instead of the FIPK, since virtually all of my driving is below 2500 rpm.

djmann02, the expense of swapping gears from 3.73 to 3.42 will never be recouped by reduced fuel consuption. It will only reduce rpm's by 150 at cruising speed, which isn't much. I also use this Tahoe for towing occasionally, so the 3.73's are much better for me than the 3.42's. 3.73's were one of my requirements when shopping for this Tahoe.

4x4 is only used on bad roads.

Do those programmers have much effect on gas mileage? I've always heard them recommended for power.

As for the speedo recalibration, can't you just buy a new $12 driven gear with a different tooth count for the t-case tail housing? That works on many NVG t-cases -- does it work on the NVG246 in my Tahoe?

[djmann02]

Everything you stated is true. Let me add a little more. The 4x4 will only decrease your gas mileage a little. The weight and drag of the extra components is what I was referring to but you cannot get rid of that. As far as the gearing goes, the 3.42 gears should be fine with what you are towing. I think there is only a 1,000 lb. difference in tow capacity between the 3.42's and the 3.73's. Yes, it would cost upfront to swap out gears and I could not tell you how long if ever you would get your money back. I am thinking RPM's only. And the mention of the Hypertech programmer was a two fold suggestion. It would not only tune your vehicle for better gas mileage and performance but you would have the options of changing the gear ratio, tire size, rev limiter, etc. It sounds like you are wanting the best of both worlds in an SUV. Good luck finding a happy medium.