why did my mpg go down

Ok so i just switched from conventional oil to fully synthetic and my mpg dropped from 16.5 to 14. my miliage is at 40000 and i bought the truck at 36k so im thinking i need a tuneup but why such a big drop in mpg. also i read somewhere that pure acetone could help with mpg by up to 20% any thoughts.

 

That's weird if any thing it's suppose to improve MPG. Did you add any weight to the truck? Did you start driving faster? Did you use a heavier weight of oil? I thought about the acetone thing but instead I drive slower.

 

maybe its opposite day?

 

nope stayed at 5w 30. driving habits are the same. i wonder why i get crappy mpg though. i would be happy if i could just average 17

 

Acetone?
Does it go in the oil or in the gas???

I have never heard of this, kind of scary to me.

 

it goes into the gas. from what ive read it said 2 oz for every 10 gallons of gas.. ok so besides the plugs should i change the wires as well or no. never really done a full tune up but i know how to change spark plugs

 

DO NOT USE ACETONE IN YOUR FUEL!

lol there's so much bad info out there on ways to improve MPG. I would go to your local parts store and get some lucas fuel treatment and dump that in there on your next fill up. I did it and it helped get me back up to 17mpg average.

 

ok lets say i change them for the hell of it what would be the best spark plug for better mpg. also is there a way to get into the computer with my scan gauge and mess with the engine so its at a lower rpm. right now at idel im at like 700

 

Acetone in gas: http://www.snopes.com/autos/techno/acetone.asp

Previouse thread about it: http://www.tacomaworld.com/forum/product-reviews/74919-acetone-increases-mpg.html

 

ok so besides the plugs any other ideas. my k&n still looks cleans i oiled it up last oil change.3k miles ago

 

Clean your MAF sensor.

 

Do the plugs, Make sure you did not over oil the K&N.
As Chris said do not mess with the engine control computer stuff.

There is no wonder MPG trick. If you check air pressure in tires to keep them up to proper anounts, control your foot, let off sooner as you approach stop signs and lights, run 65 instead of 75 on the freeways.
Carry no more weight in the truck than you need and hope for a tail wind.

Thats about it.

 

thanks people hope yall have a great labor day weekend off to the part store.