Do you buy gas from the same place all the time? In other words, is it possible that you got some 10% ethanol? I've done that a couple times by accident and ended up with a 1-2 mpg drop.

 

It is always at Costco,( no Ethanol) Always. I put in a AFE air filter and was getting great MPG and then the drop but, this is just this week. Could the air filter make the sensor burn the fuel too much? It seem to be doing fine?Why would highway and city be the same ? I tried both...

 

Have you checked your tire pressure lately?

 

Yes that was a first thought. It is hot here and they are high so that isn't it. I thought maybe the sensor in the engine was getting wrong readings because this filter is supposed to give more air. There is no oil on it just the filter. I have the original air filter. I was thinking maybe change back. Does the sensor reset itself to different driving conditions. I have been driving in town more and taking my other truck to work. I used to drive the PreRunner alot of highway. I got great mileage on my last camping trip 22mpg.About 20.5-21 average is my normal mileage, that is why this is weird to me?This is only 2weeks or so ....Rich

 

A guy I work with went through this recently on his Silverado. Turns out it was because someone siphoned a few gallons out of his tank. Gas theft is on the rise, just a thought to give another possible cause.

 

Uhh really? I'd have to say i doubt that story unless he has an older Silverado. Ever try to siphon gas from a newer vehicle...It's so close to impossible that it isnt worth the effort.
...you can't get a tube into the tanks anymore

 

They put 10% at Costco where I live.

 

Same here, which is why it's cheaper than everywhere else.

 

the first thing i'd do is disconnect the negative terminal from my battery for 10 minutes or so, which resets the computer (ECU). maybe the computer is throwing your air/fuel mixture off and resetting it would alleviate the problem.

 

I noticed something similar last week. Turns out my air filter was really, really, dirty - and my front left brake caliper decided to almost totally seize on me. Just caught it in time as there is only around 5% of braking material left on the inside brake pad. Back to the dealer tomorrow...

 

Turns out my air filter was really, really, dirty - and my front left brake caliper decided to almost totally seize on me. Just caught it in time as there is only around 5% of braking material left on the inside brake pad. Back to the dealer tomorrow...

Nice catch!

 

Did you check for leaks? Is the engine temp. hotter than normal? Have you been getting on the gas a little bit more than normal? Are you 100% positive that you didn't get E10? Have you been running your air conditioner when you would normally roll the windows down? Are you driving a hillier route than normal? Is your oil low? Has it been too long since your last oil change? Have you been hauling extra people or cargo? Did you add any mpg-reducing items to your truck (larger wheels, performance mods, etc.) Have you been leaving your truck idling in park for any length of time? Have you accidentally been towing a large boat around with you? Have you been driving with the parking break on?

Just a few things that might combine to drop your mileage.

 

Have you accidentally been towing a large boat around with you? .

sorry, i just think this one is funny.... :lol: that's great stuff right there..

 

Everyone has 10% ethanol now - The federal gov't mandated that about a month ago or so, I forget the exact timing, but very recent. It's unfortunate, I had a few gas stations I used that were not 10% ethanol, but with the new federal regulations now all of the gas stations have the "crap" gas. Along with reduced mileage and power on our vehicles studies have also showed that the ethanol mixture is not good for our smaller engines either, such as lawn mowers and such. From what I recall the ethanol is not friendly with the seals and burns slightly different. I'm sure more can be found via Google on this issue.

 

i thought it was 3% to 10%? in any event ethanol was and remains a bad idea in my OP.

 

^I agree, that's just not true. There are plenty of stations around here that are not using ethanol at all. Maybe ScottAW can direct us to an article or the Congressional Record where this is mentioned?

 

wish that were true in PA, most stations have the ethanol stickers on the pump but many say "may contain up to 10%" interestingly enough i have never seen e-85
offered anywhere in the state yet. i think ethanol is going to take a dump soon anyway in lieu of the current crop failures, shortages, soaring prices and failing livestock farms not to mention more people starving world wide because of sky high prices.

 

^I agree. Ethanol is a complete and utter failure. Anyone with a clue could see that from day one because who would actually think that using your food supply as a fuel source would be a good idea?

 

I was under the impression it was a federal mandated regulation, perhaps it is just the state of NY? Although, I do recall traveling in VT recently that all the pumps I saw over there were also marked 10% ethanol.

 

Did a little research, it appears to be a federal regulation, although not as direct as I thought it was in mandating 10% across the US, although that is now fairly common in order to adhere to the directive listed below.


Energy Policy Act of 2005
"Increases the amount of biofuel (usually ethanol) that must be mixed with gasoline sold in the United States to 4 billion gallons by 2006, 6.1 billion gallons by 2009 and 7.5 billion gallons by 2012"

http://en.wikipedia.org/wiki/Energy_Policy_Act_of_2005

 

Did a little research, it appears to be a federal regulation, although not as direct as I thought it was in mandating 10% across the US, although that is now fairly common in order to adhere to the directive listed below.


Energy Policy Act of 2005
"Increases the amount of biofuel (usually ethanol) that must be mixed with gasoline sold in the United States to 4 billion gallons by 2006, 6.1 billion gallons by 2009 and 7.5 billion gallons by 2012"

http://en.wikipedia.org/wiki/Energy_Policy_Act_of_2005

I've seen estimates that this years corn yield may be down as much as 4% because of flooding.

Unfortunately it seems it must take something like this to hit congress in the head to see how a mandate don't make it so.

 

I live in Sacramento, if the gas Costco has started selling is the 10% that would be the reason, since that would be the only change.Is there any other place to buy gas that is the regular non-10% in this area? $.10 less per gallon for a $.67 send rip off is no deal!!!!Rich

 

I think Sunoco sells "non-ethanol" gasoline.

 

I have been getting regularly going to work(Highway) and around town 20mpg. This has dropped to 17mpg same exact driving only the ethanol has switched to 10%. What I don't get is if all the stations are at 10% all from the USA ethanol shouldn't that be lowering our dependence and prices. If it lowers the amount of energy and more gas gets burned helping the air but, economically killing us , where is the good with all the bad , we eat corn not gas?

 

It Looks Like They Were Running About 5% And Have Gone To 10% In Most Of The Stations.

 

See, they slipped one by you! Knew it was required, but didn't know that there was a minimum they could use...or maybe that's why they went to 10% because they weren't complying with the AQMD's requirements.

 

Ethanol has a lower energy content per gallon than gas which accounts for your performance drop. Its main function is to replace the now-banned MTBE which is a combustion retardant used to boost octane numbers. The numbers are here: http://zfacts.com/p/436.html

Some states do require all stations to carry E10, Oregon for example: http://www.salem-news.com/articles/january142008/ethanol_11408.php

Ethanol is also causing an uproar in the boating community (of which I am a part). Some boats have fiberglass gas tanks which have to be retrofitted because the ethanol is dissolving the tanks. Luckily, I don't have this problem, but another problem with ethanol is that as it sits for long periods of time (90 days), the ethanol separates from the gas. This isn't a problem for the small tanks of cars but can be a serious problem in boats. Here's the scoop: http://www.tmcowners.com/teamtalk/archive/index.php/t-12658.html

 

Back to the mpg drop on your truck after you changed the filter......

does the filter cause the truck to "sound" better?.....this can cause your mpg to drop.

It may sound like a joke, but if your intake change makes the vehicle sound better when you step on the gas, you might be stepping on the gas more in order to enoy the sound. This will cause the mpg to drop.

I noticed this effect when I put a cold air intake and cone air-filter on my car.

 

^^^The fires aren't that bad here, but the sky has been hazy for like 2 weeks or so, and there have been 2 mornings when i've woken up and seen ash on my truck.

 

I have three 06 Tacomas. Get gas from same station all the time, drive under same conditions all the time. Drivers have not changed. One truck only dropped from 20 to 17 seven (7) tank-full's ago. The other two are maintaining the 20 mpg. I, too, am looking for answers.

 

plugs?