Gas Mileage??? WTF

hey guys i've got a lifted 98 3.4l v6 with 33's.it has an magnaflow eshaust with complete K&N cold air intake (see pics). i just figured out the miles per gallon and im get about 8.5 at very best. I'm mostly driving to school and to friends house around town. Very few stop signs. So i was wondering whats going on? Its a manual and i usaully dont shift into 2nd and 3rd untill 2800-3100 rmps and i mostly drive around in 4th doing about 2100 rpms. is it my driving?

 

it's the 33's and the v6....but still that's bad

i'm trying to figure out why i'm only getting 15/16mpg....all stock with 265/75's..auto and a light foot most of the time


might need a full tune up: filters, spark plugs, cap/rotor...i think those are dist motors not coil packs

 

ya i've be adding those gas addatives that are suppose to clean everything out. and the spark plugs are about 15,000 miles. so i dont know. mabey im a little heavy on the peddle but i drove my dad truck( 2006 f 150 2 in lift 32's v8) and it got about 13-14.

 

You may have an exhaust or intake leak. Anything that could cause the O2 to read lean will cause poor mileage.

 

so any ideas. like places/ things to check. or should i take it into the stealership or local auto store?

 

Check for exhaust leaks before or close to the O2 sensor. But you may need to take it in so they can hook up a scantool and watch the readings.

 

ill go through and change some stuff and see if it helps out but if i take it in do you have any idea what it would cost for them to figure out whats wrong/ fix it?

 

Keep your foot out of it, stock tires on mine in town 17.6-18.2 all city and I keep it as close to 2k rpms as possible. I expect that to drop a little as the weather gets colder.

 

i have tried shifting into 2nd in 2000 rpm its kinds jerky and it puts a lot of strain on the motor (and slow exceleration) cuz i still have stock gear ratio(4.10) but i dont think shifting a 3k rpms isnt that bad it would drop me to 8-9 mpg

 

Did you get your odometer calibrated after your tire upgrade? It wouldn't be off by much, but it would affect your mileage if you've gone father than it reads.

I hotrod in my truck and it still gets 12-14 in town. It's stock with exhaust but that shouldn't matter too much.

 

I also have a lifted 98 V6 3.4L w/33's and this is what I get:

City 12mpg
Hwy 16mpg

 

Wow, this makes me think something is wrong with your truck. I have a 4x4 V6 96 model and I get 20 mpg in town. Don't drive on the highway so no idea what that would be.

I run 31's but 33's can't hurt mileage THAT much.

Maybe take it in and have it put on a diagnostic system to see if they can determine what's going on.

 

I might have done my calculations wrong...I'll track a couple fill ups on fuelly.com and post the results...

 

i also have a 98' with 3.4 w/32's. my truck never sniffs 3000 rpms and all i get is 14mpg. sea foamed it about a month ago with no real results i dont think. plugs probably got 10000 miles on them, air filter is clean. i cleaned the MAF about 5000 miles ago. has anybody replaced the O2 sensors with good results?, wanted to ask before i did it because they are a little pricey.

 

my gas mileage barely changed at all from the stock size tires to 285's. it isnt ur driving, i shift at 3k for every gear. u could try removing your o2 sensors and giving them a cleaning before replacing them,since theyre fairly expensive.

 

I would go with a vacuum leak or exhaust leak I have 33's and a s/c and have a lead foot and get around 15mpg average.

Spray carb cleaner around your vacuum lines see if the rpms change then look close at your exhuast see if there is black soot around a crack or anything. Besides that it could be a sensor throwing a lean condition in. just my 2 cents

 

20 mpg City!!! that's amazing...You've well exceeded 15 mpg Edmunds specs...

http://www.edmunds.com/used/2002/toy...156/specs.html

 

I only checked it once. Need to check it a few times to be certain. I do drive like a little old lady from Pasadena though.

 

How do you adjust the speedo. Mine seems to read low.

Flash

 

Its not like the old days where you had speedo cable coming out of the back of the tranny. Its all fly by wire now.

There is no way to adjust the speedometer/odometer in our trucks.