Ok so i just filled up and did the math and right now im getting about 14mpg.
so i also about a month ago did the plugs and wires
I today i checked the gaps all to spec
I have no check engine lights on
And now i don know what else could cause this
and a side note the transmission has now started to shift rough as a biatch

 

Well, first things first, what math did you use?

 

i did (capacity of the tank)19.5 / 4 x 3 = 14.625(because it was at 1/4 tank) than i did 215 / 14.625=14.700

 

Ok, thats why. That is totally inaccurate and useless. You can't do it that way.

Fill up
Reset trip odometer
Drive until your almost empty
Fill up
Miles divided by gallons pumped = MPG

 

ok thanks
and about the transmission
like a week ago it started sputtering when it shifts and now it rocks the hole truck when it shifts

 

I get 15

 

Math or not, it still sucks on gas.

 

well if thats for your truck in your avatar than thats because of thoughs big tires u are running my truck i almost completely stock and a 3.0 and wen i bought it it got 20

 

Exactly....driving home from Pittsburgh to northeast Pennsylvania, I averaged 20.6 highway driving in a 4.0L OHV with an Auto tranny and 157,000 miles.....no way you should be getting that low of MPGs....I average 17.5 every week.

 

Oh, I figured you had atleast 33's on your truck. Bad upstream o2 sensors?

 

im runing 28s

 

i get 15-16 town and 17-18 highway with an auto and 4.10's and the 4.slow and for the tranny problem take it to a shop that flushes the entire tranny

 

well i cant do the flush right away atleast a couple of months is that goin to be a problem ?
also i have a 3.0 it seems you all have 4.0

 

Bought my 3.slow I got 20mpg with 235/75/16. Put on the 32's. Got 17mpg.

Now im getting about 15.5mpg for some reason...Dunno, its black magic I tell ya.

 

well i drove to the keys last weekend and got 280 miles out of a tank, and boy, my truck is the roughest runnin mazda on here, but 280 miles for a 16 gallon tank thats the best mileage i have ever gotten with this truck, stock or lifted, so yea, i am now a true believer that its the driving conditions, cause here i am back in ft lauderdale and get 73 miles to a half tank, stop and go traffic, and then driving to the keys was wide open rural roads, or in traffic, in a straight line doin 45 mph

 

Running 30x9.5x15 with the rest of truck stock I get an average of 20 mpg. Only because I'm running 60-65 with no traffic for 50 miles to and from work. Depending on tires , pressures, sizes and habits along with the once in a blue moon traffic crap I get big differences (seen it down to 17). Towing my 2900lb boat I get around 11 mpg.... Luckily or should it be unfortunatly I don't get much time off so I don't worry about towing. I keep the pressure as close to 40psi as I can for my best mpg.

 

(sig)
That's why your mileage isnt working