Clemsonfan15

So I fill up my gas tank sometime last week and this time I add Marvel Magic to the gas. I heard about this stuff from a guy at Lowe's and figured I would try it, so I did. This stuff worked great. I got 150 miles to a half tank, but after that my mileage dropped.

After I got to a half tank I performed the deckplate mod and added a K&N air filter. I thought that these two upgrades should get me better gas milage, but boy I was wrong.

I kept my driving style the same, so I decided that was not the cause.

I'm really confused. What caused my gas mileage to drop so much. 150 miles to the first half tank, but then 90 miles to the second half tank AFTER the upgrades.

I need ya'lls help.

Jay204

O2 sensor ?

Team420

what year/engine/5spd or auto? So you got 240mi to a full tank....what do you usually get? you cant measure fuel mileage within half a tank, you need to run a full tank to accurately determine mileage. My truck does the same thing EVERY time I fill it, and has for the 6 years I have owned it.

Clemsonfan15

I have a '98 Limited 3.4L automatic.

I was getting like 240ish from a full tank, so the upgrades had no effect in theory.

kmcaprice14

I have never owned a toyota with a linear fuel gage. I always get most of my mileage on the first half a tank, and substantially less on the second half. The last quarter of a tank gets me like 30 miles....

and at the end of the day, how do you figure your mileage dropped? 240 a tank to 240 a tank... sounds the same to me.

K&N and deckplate wont really do anything to boost your mileage. With the K&N I put on my IS300, I would wager to say my mileage actually dropped a hair.

slisdexia

check the miles per gallon, otherwise you're just throwing darts blindfolded, and the only real way to check gas mileage is to fill the tank up the same way everyime(one click or five, just be consistent), and divide miles driven on that tank by the number of gallons filled. Remember, be consistent. I had a Subaru where I could get 250 miles on the first half, and then 75 on the second half. It's just the way that everything is designed.

Clemsonfan15

Yeah. All of ya'lls ideas are right on. It really isn't a drop I suppose in overall mileage.

On the subject of mpg: Before right at 17 After(Filled up tonight)-17.25

So by adding these things I gained .25 mpg. Maybe I just had a goal that was too high.

I think the fact that the gauges aren't correct must the main problem.

ciscojay

My 3rd gen fuel gauge is all over the place after a half tank. I can go from just under a 1/3 tank left to showing the gas light if I drove down a long downhill. I'd only trust mileage difference by running through full tank as dry as you dare.

If you still think your mileage is dropping try another can of what you're using (or preferably some BG44k) to a half tank and run it hard for a few miles. Sometimes adding an initial doseage to a dirty motor can actually losen up enough carbon deposits to build up in your cat and clog that up a little bit, hurting your mileage, and in extreme cases some power loss as well.

scuba

i think i got around 250 on a tank in my 99 2.7 5spd
so in the 3.4
your lucky

although, ive got a quick left foot and a heavy right

Man4God

Yeah, 240-250 is about standard if it is mainly cityish driving. My first half of a tank I usually never get more than 115. The gauge is stupid and really should be ignored. Go by how many miles you have traveled. Much better gauge.

Clemsonfan15

Thanks for the information everyone.

cackalak han

Please try to help the guy and not leave him stranded somewhere or make his fuel filter clog up faster. Your method is not any more accurate than what he is doing right now. In other words, DO NOT DO THIS!

http://www.wikihow.com/Calculate-You...ficiency-(MPG)

That is how you calculate Miles Per Gallon. Miles Per Tank means jack $#@!. It is not consistent nor accurate. Use the link above and post up what you get. You should be somewhere in the 15-17MPG in the city and 20+ on the highway.

EDIT: Skimmed through the thread the first time and missed that you already got the MPG figure. 17MPG is about right for city driving. Also, even doing the above method will have margins of error, as there are too many variables to give an accurate figure each time (driving method, terrain, weather, gas, gas pump, etc.). You need to do it several times to get a more accurate MPG. Therefore, you cannot say you "gained XXMPG" from a single fill up.

mkgarrison5

dang 240ish for a full tank?? i easily get 300 miles or more in my taco with 265/75/16's... i do however drive a lot of highway. that is an average with 16 gallons of gas used so thats around 18.75 mpg give or take...

btw ditch the K&N filter.. no need for it bc it wont do squat for you unless you have headers or whatever... oiled air filters are crap guys

ciscojay

I still get around 300 miles per tank, even with the charger. I've gone up to 330, probably with only fuel left in the line from the tank. And as dry as your dare means you'd be partially retarded to strand yourself somewhere just to see how many miles per tank you could get. I'd hope that people on here aren't that dumb...like you Han...may assume. duh! THINK!

cackalak han

If you think that was flaming, grow some thicker skin. I was merely questioning your logic. Why would running your tank as dry as possible (without going completely dry) be any more accurate than filling up half-way through? Or at the 3/4 mark? Either way, those figures mean nothing. Nice try, though.

Clemsonfan15

I see the facts clearly now. The gauge is just not accurate. I was doing MPG even BEFORE doing the mods. I got about 15.xxx when I first got it about eight months ago. Since then it has increase to 17.25 when I filled it up last night.

I was just expecting too much out of the new air filter, deckplate mod, and Marvel Magic.

mkgarrison5

marvel magic is crap, K&N oiled filters are way way crap... deckplate mod is useless too unless you just want it for the extra noise

pineapple

$3.84 / gallon regular! My22re is parked and the Corolla has become the DD. Going to have to do something about my wife's 3.4 Taco w/A.T.

mkgarrison5

pineapple, sell one of the trucks and get another corolla.. i feel your pain. the gas prices wont get much better guys. we will never see gas below 3 bucks a gallon.. may not even see it under 3.20 a gallon ever again..

Clemsonfan15

I'm not really sure about the first two statements yet, but I haven't noticed any extra noise from the deckplate mod. It sounds the same.