Ive been told fuel filter being clogged will reduce mileage. I have a 01 with a 4.3L and automatic with 3.42s in the rear. I have 151,000 miles. Still running original plugs, wires, O2 sensors, and until a month ago... Cap and rotor. I did change the fuel filter around 100,000 miles. I drive all highway to work, but get 19.5 - 22 mpg. When I drive mostly city I have never gotten under 17 mpg. I have also cleaned my MAF a couple years ago. Running a dirty filter will not affect mileage. Your MAF will sense the airflow and fuel is adjusted accordingly. That is if you are running a 4.3L.

I only changed the cap androtor because I had to have a shop replace the intake manifold gasket. They removed the cap and rotor and informed me of its condition. I knew what it was, just told them to replace it since they just charged for the part. No labor because they were already there.

I run mobile1 5W30 with 3.5 qts with 1qt Lucas synthetic. I run that anywhere from 5,000 miles to 7,000 miles with a mobile1 filter. I change the filter on every oil change.

Hope some of that helps. Good luck! Maybe someone else will chime in with more info if not.

Oh, also.. I'm running 245/50/16 tires at 35 psi. and ext.cab. I also run a WIX paper air filter. just for comparison data.

 

the main issue is you are driving short distances, so the eng never reaches operating temp so it can recoop some of the extra fuel it used during warm up. running open loop is a rich condition most of the time.

short distances kill gas mileage.

 

The short distance driving kills fuel mileage, and so does winter with colder temperatures and because you have weight in the back. My mileage dropped down to about 15 now because of the weather and I drive roughly 250 miles every 1 1/2 weeks. I usually get between 17-18 where I live in the summer months, and I have four wheel drive.

 

Could also be extended idle times warming the truck up and "winter blend" fuel mixtures the gas stations run during the winter also affect mileage.

I'm assuming you have an auto, the ECM will keep the trans out of lock up when cold to provide quicker warmups. This could also be hurting your mpg.

I don't think all the above would equal such a drastic drop. You usually cannot smell a FPR leaking on a vortec as they are mounted inside the intake on the back of the injector pod. You have to take a small light and mechanic's mirror down into the TB to look for clean / wet areas in the intake.

 

everyone pretty much said what I was going to say about whats hurting it.

Short distances
Colder temp outside & operating temp
More weight in the truck
Winter blend gas.

 

stock size tires (small 205/75/15), inflated to 40 psi.

wow....
your truck must ride like a covered wagon.

 

Why are your tires inflated to 40 psi?

 

At even 35psi, my truck seems to labor over bumpy roads, as if the softer tires causes a delay in the response from the suspension. But my dime seems to like 40psi a lot and handles hell of a lot better.

I have the heavy duty Z85 suspension on my truck.

 

my maf was dirty and dropped my mpg without putting on the cel
i put on just over 5000km last month and had a avg mpg of about 20
avg air temp was -5C

 

I've aired mine up to 35 psi ( and suffered the tough ride)
for fuel economy reasons a couple of times before, only to
find it made no significant difference in gas mileage over
my usual 28/20 psi settings.

 

I know it's counter intuitive but my ride is smoother and softer, and feels a lot healthier/nimbler with the tires set at 40 vs 35 or 32psi. And if there's a factual basis for why that is -- take your guess. It might be that the Z85 has a lot of 'stiction' built into it due to the stiffer spring rates, in which case softer tires would function more as a sort of out-of-tune presuspension for the truck while not being soft enough do anything but absorb some road noise. That's my guess, anyway.

With the 240+lbs of weight in the bed there lately, the ride feels real nice.

 

Same problem here..

I have a 2001 s10 4.3 v6 vortex.
After doing the calculations, mine came to only 11.84 mpg.
Really low

Anybody know of anything to help with this.. Upgrades?
Mine is all stock, on 235-75-r15 tires and I do all city driving, 50% at 45 mph with the 3rd gear at 2100 Rpms. 50% at 25mph at 1600 Rpms in 3rd gear.

Thanks alot!

Thanks

 

Most of the time when I don't get good MPG, it is because my tires are low on air pressure. You might need to check your air filter and fuel filter. Alot of in town driving will hurt MPG. The faster you drive, the worse the consumption of gas is. Bad MPG will not trigger your CEL, unless a part is operating outside of the factory settings.