I'm losing MPG

I've went down from 24.1 to 23.8 in the last few months of 2011. Now I've dropped again to 23.6. I have a 986S 2000 registered. Around 67,000 on the clock. I bought it in June 2011 with 59,000 miles so I've driven the car a fair bit because I enjoy it so much. In terms of usage I mainly go for a decent run to see my folks (100 miles or so) but I'm not adverse to popping down the shop occasionally. I try and keep the revs above 2k no matter what and tend to shift up at 4k and then back down at 3k. Unless I'm in the mood for fun and then I use the 4-6k range. I try not to go above 6k. Is she just getting old? I don't care I'll keep replacing parts but I wanted to check I wasn't causing damage. Any thoughts appreciated. Harry

My '07 has 44,000 miles on it. I've never gotten close to 20mpg, but I think that has everything to do with the way I drive it :banana:

maybe winter and a few lbs. lower pressure in the tyres? That's what I would check first then the air filter. that is not too big of a drop though. I wish I got that gas mileage, for some reason I get around 17mpg and my wife see it and says " I thought you said this car was more fuel efficient than your Benz?" LOL, it is on paper....:burnout:

Check tire pressure, or try switching off the sport mode :drivingskid: The gear changes there do not sound like anything that would be a concern for the car.

Interesting. I used to be at 24.x mpg on a regular basis now I'm at 21.5... I just thought it was due to the warm weather and fun driving and was going to see if it climbed back up in the cold months ahead... Now you have me thinkin' My tire pressure is fine, I check it regularly... Any other reasons why it may have dropped?

Forgive me if I'm wrong, but didn't there used to be something called "winter" gas where the mixture (ethanol?) of the gas was adjusted to deal with lower temps in certain areas of the country? If so, maybe this mix would correspond with the lower mileage. Now you just have to wait for spring and "summer" gas to see if your mileage improves!

several useful recommendations mentioned above... 1) Tire pressures low 2) Air Filter clogged 3) Car running rich ( O2 sensor (s) going bad??) - does the exhaust stink of gas? 4) I too think that ethanol gas delivers worse mileage... your mileage is still better than most... I'm getting 22mpg (all purpose miles) JT

In my current DD (Acura RL), I always use to see my mpg go down in the winter and back up again in the summer. Like PistolPete ... I always attributed it to the gas mixture change at the pump. (In MA, so winters get a bit cold here ... like today, <10F this morning.)

I'm surprised anyone even checks mileage. If the car is running good and I'm having fun, mileage is the last thing I think about. In fact I haven't even looked at it in a couple months. The differences seem so minor I wouldn't worry about it. Not even sure how you'd really test it unless you took the same roads, shifted at the exact same rpm, got the exact same red lights, had the exact same temperature in the exact same "gasoline season" and had the exact same tire pressures. Then there's the exact same filter conditions and on and on. Just enjoy the ride.:cheers:

Then you're not really driving it :taunt: With the colder air temps the car will see taht it can add more fuel and provide more eprformance, so whilst you may not notice it you acceleration may be a tad bit quicker and that will cost you more fuel. If you had seen a drop in a few mpg then there might be some concern, but by such a small amount just get out there and enjoy it...it's a sports car it likes to drink fuel

Fuel mileage has dropped as well in my 07 Cayman to 24 MPG, but that happens every year as they switch to the winter fuel mix. Once springtime arrives I should be able to get the 25 MPG that I'm used to.

My main concern was that everything in my engine is running ok and not causing the drop off in mpg. Thanks for the info.

Thanks guys. I'll check those little things but it sounds like I'm being a bit anal. Am I really ok going much above 6k? I thought 4-6 was the sweet spot?

4-6k is the sweet spot, but when you shift you want to end up back in that same range again so it is better to go higher in the revs and when you shift accelerate faster. The car has an electronic rev limiter so using your right foot to go above 6k is no problem, and it is great to get the flat-6 screaming and it was designed this way so use it

You most likely need one of these.... 40+ mpg! :taunt:

K-Man, that car looks pretty cool... forgot that you decided on a hyundai (sp??) and initially thought it was one of those new hybrid lexuses... nice regardless... but I don't see a third pedal... :wink:

I also agree with the gas factor. In colder climates gas stations do change their gas to handle the temperatures.

Wow!! I also forgot you went with the Hyundai. Nice looking car and I also agree I don't see a 3rd pedal.

This is a very accurate and good post as many states switch to a 10% ethanol blend in October and others in November. The ethanol while burning cleaner requires about 1.3 gal to 1 gal of gas. Now granted it is at a 10% additive it is still a reduction and causes a reduced MPG or HP in cars. Now should the orig OP in his location not have the ethanol added then check the MAF. Remove it and clean it. Another check in which is not common would be to get gas at another gas station in re fueling to make sure the grade is correct. Let us know on these points as Darchenia pointed out the most direct and best answer for most US states yet not in perhaps the EU. Best , Scott

Thanks for starting this thread my gas mileage suddenly dropped from almost 23 mpg to 19 and my car is running great. I've also noticed my mileage calculator, on the OBD , is showing about 15 miles less on a full tank than normal. It appears the cold temps are the cause.

Except those aren't pics of MY Veloster. I'm out of town and car is at airport, rest assured it is a 6spd car and I've been able to get 47mpg highway but my average is around 34 because I tend to be in a hurry . Great little cars, handle well, stop well, plenty of amenities and storage space capped off with great mpg and for $22k you've got a winner! --- I am here: http://maps.google.com/maps?ll=42.947853,-87.900549 Sent from my iPhone using Tapatalk which means I'm probably traveling at the moment so please excuse any brief or hurried replies, spelling errors, etc. Etc.

Well I have a bit more information today that might help with the diagnosis. After a long drive yesterday I thought by the end of it the engine was misfiring. My standard procedure is to sleep on it and see what the situation is the next day. Well today the misfiring is unmistakeable and there is a loudish knock from the near side rear of the car. It's so bad that I had to turn around on my way to work and bring the car home because I wasn't certain I'd make it.

Any ideas guys?

Sorry to hear about this. The first thing we need to do is to get a code reader and see what codes were tripped before we can narrow things down. When I had a misfire, my dealer checked my coilpacks and spark plugs as the first step.

Thanks Pete. I've put the car on a flatbed lorry and taken it to my garage. I spoke to my retired father who persuaded me I'd feel might stupid if I tried to drive it there for the sake of saving £100 only to cause serious damage on the way. I'll keep you updated. Everything's fixable and theres no such thing as a budget for something you love I guess.

Just spoke to the garage. They're doing more tests but they've highlighted an issue with the "air mass centre". I'm googling it now. Doesn't look too disastrous.

That's the Sensor "Softronic" mentioned. I read in Consumer Reports the car testers get 30% less MPG with E85 compared to E90.

It's not just Oregon. Ethanol is all over the mid-West also. I don't really understand why folks think its better. With current production methods it takes about as much energy to produce as you get out. It's a hydrocarbon so you get the same emissions albeit at differing levels due to the different composition. The end user pays the same price for less gas mileage. So you burn more with the corresponding emissions. Somehow I think the only winners here are the folks growing corn and producing the ethanol.

Ethanol blends gums up engines something terrible, it's really noticeable on gas powered tools we use around the yard such as chain saws, blower, lawn tractor, hedge trimmer, etc.. I shudder to think what it's doing to cars

Ethanol free gas is available, but the stations are few and far between. This site is somewhat accurate; hope this helps. Ethanol-free gas stations in the U.S. and Canada

Thanks for that, I think it's outrageous that we're forced to use fuel that reduces mpg and has a negative effect on the performance of your car (and other gas powered machines you use). I've been following the debate here Ethanol Free Premium Coalition The Problem With Ethanol / The Three Phony Assumptions ​ Phony assumption #1: ethanol will reduce the price at the pump. Sometimes it does, sometimes it doesn't, it is an agricultural commodity subject to all the vagaries of speculation in the futures market. Phony assumption #2: ethanol will improve air quality. There is no proof, nor any way to prove this statement. For every study that says ethanol will improve air quality there is another study that says it won't. There are studies that say it will reduce certain green house gasses and other studies that say it will increase other noxious chemicals. This argument is dubious when you consider the clearing of rain forests in third world countries to either plant more sugar for ethanol or to replace the loss of food crop imports, especially soy beans. Phony assumption #3: ethanol will reduce our dependence on foreign oil. Just because you say this over and over it doesn't make it so. Nobody actually knows if it is true. There has never been a statistically significant, large scale, independent study of mileage before and after a mandatory E10 program. Without such a study there is no way to prove this statement. Nobody knows how the engine control units in cars respond to E10. It is clear that some handle it better than others, because there are many reported cases of mileage decreasing 10% or more, which would indicate that a lot of cars are using more gasoline than before the ethanol mandates. Who knows how many? Where is the data? What Needs To Be Done In Oregon ​ The Oregon mandatory ethanol law has been superseded by the federal RFS mandate EISA 2007. The state mandate needs to be repealed for two reasons: There is no escape clause in HB-2210. Now that ethanol is more expensive than gasoline, Oregon has the highest gasoline price in the four Northwestern states according to AAA . (Be sure to take the tax out.) No matter what the price of ethanol, Oregonians will have to pay it. Even worse, if ethanol becomes unavailable for any reason, mother nature or shortage because ethanol companies go bankrupt and can no longer deliver, then gasoline distribution must cease. If a terminal can't get ethanol, it cannot ship gasoline, especially if all of its blending stock is suboctane. SB-1079, the promised relief for the people who can't use ethanol blended gasoline in certain engines doesn't work. Large areas of rural Oregon have no access to unblended fuel. SB-1079 does not prohibit suboctane production of premium unleaded. If premium unleaded is taken suboctane, which is rumored, SB-1079 will be worthless. The mandate needs to be repealed and a new law passed prohibiting the blending of ethanol in premium unleaded gasoline. Repealing the mandate and prohibiting ethanol blending in premium unleaded will not interfere with the ethanol mandate in EISA 2007, because EISA isn't an E10 mandate. Oregon will see no change in ethanol blending in regular gasoline unless EISA 2007 is repealed. If premium unleaded gasoline is not protected from ethanol blending there will be a direct negative impact on aviation and other SB-1079 constituents in Oregon.

I have had my 06 Cayman S since Sept and I can hardly get over 19mpg and this is a mix of city and highway driving and very rarely stop and go. I am kind of disappointed as I thought I could at least do better than the Subaru STi that I came from. The STi averaged around 22-23mpg no matter what, city or highway was the same. I have not changed my driving habits and shift right around 2k rpm and rarely do I get on the hammer lol. I have read air filter but the car was just serviced before I purchased, any other suggestions?

If some simple maintenance is an option, go to the parts store and get a can of CRC MAF cleaner and a new air filter. Clean your Mass air flow sensor change the air filter and see how the mileage goes up. CRC claims you can get some significant mileage gains. With all the oil the Caymans have in the intake it could help. I get horrible mileage. As long as there's gas in the tank I'm happy. The wife gripes O well