Why all of a sudden has my gas milege dropped from not great to oh S--- I need gas again. The truck has 110,569 miles plugs changed @ 99,902 with OEM plugs. I use $75.00 of gas a week and only drive 20 milis a week to work and back. If I drive 30 miles at 65 mph I'll use a quarter tank.

 

Check air pressure in tires, check air filter, run some Chevron Techron or Berryman's B12 cleaner. I would also check and make sure you don't have any fuel leaks anywhere.

 

how far are your commutes? i need specific distances.


if you only drive 20 miles in 5 days to and from work, there is no way your truck is getting up to operating temperature.

 

Someone siphoning fuel from your tank?

 

Have you changed to taller tires lately? Or softer compound? I recently replaced my tires and lost 1.5 mpg due to a softer tire.

 

I did all the normal things that were suggested. Tires are low on tread but meet minimun spec for state inspection. No tank leaks and I use a locking gas cap. Just had the passenger side manifold replaced need the other side I'm sure.Fuel and air filters changed not long ago.This truck was never great on milege but now it's really bad.Most of my buddies drive bow ties and get way better milege than me. My comute is 20 miles a day round trip.

 

Is the truck throwing any codes that you know of? Maybe take it to Auto Zone and have them run the free code check on it. Could be a sensor causing an issue.

 

No codes but I didn't get a code before the trans went out. I took it to get the plugs changed at 99,9000 miles and didn't get it home. I pulled out from the shop and it shook the heck out of me went back to the shop and they towed it to the trans shop. It couldn't hurt to get it checked.

 

Don't forget we are using a winter blend of fuel now....that kills mileage somewhat .

 

edit

So, just to clarify.. your first post said 20 miles a week using $75 in gas.
But in a more recent post you mentioned 20 miles round trip a day.
Guessing you work 5 days a week, that would be 100 miles a week using $75 in gas.
Fuel average costs are around $3.50 a gallon?
$75 should all but fill your tank.. 22 gallon? I dunno... somewhere in there.
That puts you around 4.5mpg...

I think you should calculate your "actual" mileage.. I think it is a bit exaggerated atm. Not saying it hasn't gone down but it is unlikely those numbers are anywhere near accurate. Might be why people are asking if someone is stealing your gas or if you have a leak.

It would help to know what engine you have as well.

If you still have a manifold leak, your 02's will be reading off, which will drop your fuel mileage significantly.

 

If it's THAT bad, you have a leak or you have fuel injectors stuck open. You sure it's not blowing black smoke?

 

how long do you let it idle before you take off in it? do you sit and work and let it idle??

 

+1 to Toyz and Sam

I've noticed my mileage go to sh*t as well here in SE PA. I don't know how bad yet, but will this weekend when I make my trek north. My wife's Subaru went down 3 mpg just from the winter fuel blend.

 

5.4 L engine,no codes or smoke. The engine runs strong and I don't let it idle long. My work comute is 15 minutes with hiway and city driving. Used a can of seafoam last fill up. I used GET GO gas the last few fill ups but usually use BP. I would guess the milage is close to 8 mpg which is terrible. I hate taking it to the shop for this my machinic retired and the guy who bought the shop is a GM guy.

 

O2 sensors?