No toys or blue hair, but I do have a light foot and am fuel economy conscious and besides; I only drive downhill with a tailwind.

Here are things that I do that may help my MPG:

I use synthetic motor oil.
I use regular 85 octane gasoline (87 when in lower elevations).
I removed the honeycomb screen at the front of the MAF (doing this voids the warranty on the MAF).
I try to avoid using cruise control, when I hit a fairly decent grade I will allow some speed to bleed off and then recapture it on the downhill, cruise control will hold the speed dead-on but this is not usually the most efficient method of operation.
I avoid using full throttle and jackrabbit starts (unless I have to bust a move to keep from getting run over).
I don't use Auto-Start or let the vehicle sit idling while warming up, I get in start the motor and drive off, I take it real easy on the motor until it reaches normal operating temperature.
I do not carry unnecessary items in the vehicle to keep the weight down as much as possible.
I removed the crossbars from the luggage rack (never have had a need for a luggage rack in my life).
I keep my tires pressures at 10% above the door jamb sticker, I check and adjust them at nearly every fill-up (sticker says: 31psi all the way around I run at 33psi).
My best MPG is in the summer, the local winter blend (10% Ethanol) fuel reduces my economy by about 5-10% this time of year.
I also find that I seam to get better economy on some brands of gasoline then I do on others, so shop around.


Not one of these things alone will make a detectable difference (except driving style) but all added up should have a positive effect.

 

Is the purpose of the MAF screen to just protect the MAF in case the air filter goes TU and lets something thru or even part of itself?

 

Exactly, it is to prevent a large potentially engine damaging piece of debris (such as a grasshopper or leaf) from entering the engine in the event that the air filter element is mistakenly not in place.

 

I have an 05 silverado 5.3L 4x4 automatic with a GU6 3.42 rearend. I have a chance to get a 2002 silverado 4.8L 4x4 manual with a GU6 3.42 rearend for a parts truck. I do no think the engine size shouldnt matter correct. The main concern I have is one is an automatic and the other manual?

Are these rearends interchangable both are GU6 3.42

 

I have a 2008 Tahoe LTZ, 31,000 miles to date. Original owner. Rear is 3.73. I tow a 3200# boat about once a week during fishing season. I'm an average driver, vehicle has always run terrific. My MPG without the boat is an average of 15.5mpg. With the boat it goes down to about 13mpg.

 

Yes, the two rear ends should be identical, and parts interchangeable.

 

has anyone changed out an axle in the past? I have a 2007 1500 LS 4x2 and my differential went out. I was thinking about changing out the rear axle from a 3.4 to a 4.10

has anyone done that...is that a simple swap?

 

The difference between the hi and lower ratios you mentioned is substantial !
Are you sure you want that drastic of a change ?
Going to Tow. do mud, rock...what ?

 

No not doing any of that....my suburban is basically a big old station wagon...kid hauler.....

The mechanic told me I would get better gas mileage going to the bigger rear end...and with so many miles on the truck it would reduce the engine wear....but I can't find that confirm his statement anywhere.

 

The likleyhood of you getting better gas mileage is not likely.
The 4:10 is going to spin the Drive Shaft/RPM about 25% faster at the same speed, causing more motor miles than with the 3.4. The lower gear will make the ride more "powerful' (like for Towing), which I don't think you're interested in...so...

1) Either you misunderstood him...
3) He doesn't know what he's talking about...
3) He's trying to get work that you don't need...

If you're going to replace the gears, I'd stick with the 3.4 or 3.7 at the highest.