Lost MPG
11-24-2009, 01:38 AM
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Lost MPG Hi folks,
I've got an 02 WS6 A4, only had it for a few months. I used to average 26 mpg on the highway. Lately that's dropped to a consistent 22 mpg. I haven't changed anything. I've checked the basics, such as air filter, tires, air pressure, oil, oil filter, all seems ok. No obvious noises or engine warning codes.
Can anyone give me some advice on things to check? Anything generic or LS1 specific?
Much thanks. This is really bugging me. I know we don't buy these cars for the stellar mileage, but losing 4 mpgs for seemingly no reason is frustrating!
I've got an 02 WS6 A4, only had it for a few months. I used to average 26 mpg on the highway. Lately that's dropped to a consistent 22 mpg. I haven't changed anything. I've checked the basics, such as air filter, tires, air pressure, oil, oil filter, all seems ok. No obvious noises or engine warning codes.
Can anyone give me some advice on things to check? Anything generic or LS1 specific?
Much thanks. This is really bugging me. I know we don't buy these cars for the stellar mileage, but losing 4 mpgs for seemingly no reason is frustrating!
Last edited by Schmalgar; 11-24-2009 at 01:44 AM.
11-24-2009, 05:41 AM
#2
plugs, wires, coils, fuel filter to start. did you switch brands of gas? stick to shell, mobil, chevron etc... dont use mom and pop stations. do a complete engine cleaning. clean the top end with Mopar Combustion Chamber Cleaner(search for it on here). go buy a bottle of gunk engine flush and change your oil. that will clean out your bottom end. for your injectors run a can of seafoam through the tank
11-24-2009, 06:55 AM
#3
This is a common problem that people have when gas prices go up... (Like now.) I just filled up yesterday and almost passed out when I got the bill.
How have you been tracking your mileage? Have you kept a detailed log of the type of driving you have done along with the mileage and pump readings? A lot of people "calculate" mileage from their gas tank gague, which is far from accurate. Depending on an individual run on the highway, you can get different mileages - which is why you should keep a log over a long period of time so you can iron out any fluctuations. (Over a 8 month period, my highway mileage fluctuated by 6 mpg - just because of the driving conditions.)
How many miles are on the car? Do you know what its been used for in the past? Just a daily driver? Does it have any modifications?
It is possible to get stellar mileage on these cars. They are much lighter than later model cars and do really well. On one highway run after a carbon cleaning, I got between 29 and 30 mpg.
How have you been tracking your mileage? Have you kept a detailed log of the type of driving you have done along with the mileage and pump readings? A lot of people "calculate" mileage from their gas tank gague, which is far from accurate. Depending on an individual run on the highway, you can get different mileages - which is why you should keep a log over a long period of time so you can iron out any fluctuations. (Over a 8 month period, my highway mileage fluctuated by 6 mpg - just because of the driving conditions.)
How many miles are on the car? Do you know what its been used for in the past? Just a daily driver? Does it have any modifications?
It is possible to get stellar mileage on these cars. They are much lighter than later model cars and do really well. On one highway run after a carbon cleaning, I got between 29 and 30 mpg.
11-24-2009, 10:22 AM
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Hitmanws6,
Yes, I use brand name gas consistently. I am surrounded by BPs so I use BP premium. I did use a bottle of FTP engine treatment on my last oil change.
I will search for the Mopar Combustion Chamber Cleaner and seafoam. Thanks for those suggestions!
-----
wssix99,
Yes I have been tracking it. I have a specific 120 mile rount trip that I make every couple of weeks, I've been using that to track mileage. I've been pretty **** about it too. I fill up right before I get on the interstate and right after I exit, and most of the interstate driving is consistent at the same speed on cruise control. I don't think there is much variation in the test driving. But you are correct, I haven't had the car long enough to really measure the mileage over the long term.
It has 42k miles. The only mod I am aware of is a K&N filter and Corsa catbacks. I bought it from Carmax so wasn't able to really get alot of details from the previous owner. I made a (hopeful) assumption that a 7 year old car with less than 40k when I bought it was well maintained, but I don't know.
And I agree, I had a 98 TA that got 30 mpg. That's one of the reasons that the current 22 mpg is bugging me. I know it's capable of more! Of course, the 98 was an M6...
-----
Thank you both for the quick feedback. It's appreciated!
Yes, I use brand name gas consistently. I am surrounded by BPs so I use BP premium. I did use a bottle of FTP engine treatment on my last oil change.
I will search for the Mopar Combustion Chamber Cleaner and seafoam. Thanks for those suggestions!
-----
wssix99,
Yes I have been tracking it. I have a specific 120 mile rount trip that I make every couple of weeks, I've been using that to track mileage. I've been pretty **** about it too. I fill up right before I get on the interstate and right after I exit, and most of the interstate driving is consistent at the same speed on cruise control. I don't think there is much variation in the test driving. But you are correct, I haven't had the car long enough to really measure the mileage over the long term.
It has 42k miles. The only mod I am aware of is a K&N filter and Corsa catbacks. I bought it from Carmax so wasn't able to really get alot of details from the previous owner. I made a (hopeful) assumption that a 7 year old car with less than 40k when I bought it was well maintained, but I don't know.
And I agree, I had a 98 TA that got 30 mpg. That's one of the reasons that the current 22 mpg is bugging me. I know it's capable of more! Of course, the 98 was an M6...
-----
Thank you both for the quick feedback. It's appreciated!
11-24-2009, 04:44 PM
#6
Hitmanws6,
wssix99,
Yes I have been tracking it. I have a specific 120 mile rount trip that I make every couple of weeks, I've been using that to track mileage. I've been pretty **** about it too. I fill up right before I get on the interstate and right after I exit, and most of the interstate driving is consistent at the same speed on cruise control. I don't think there is much variation in the test driving. But you are correct, I haven't had the car long enough to really measure the mileage over the long term.
It has 42k miles. The only mod I am aware of is a K&N filter and Corsa catbacks. I bought it from Carmax so wasn't able to really get alot of details from the previous owner. I made a (hopeful) assumption that a 7 year old car with less than 40k when I bought it was well maintained, but I don't know.
And I agree, I had a 98 TA that got 30 mpg. That's one of the reasons that the current 22 mpg is bugging me. I know it's capable of more! Of course, the 98 was an M6...
-----
Thank you both for the quick feedback. It's appreciated!
wssix99,
Yes I have been tracking it. I have a specific 120 mile rount trip that I make every couple of weeks, I've been using that to track mileage. I've been pretty **** about it too. I fill up right before I get on the interstate and right after I exit, and most of the interstate driving is consistent at the same speed on cruise control. I don't think there is much variation in the test driving. But you are correct, I haven't had the car long enough to really measure the mileage over the long term.
It has 42k miles. The only mod I am aware of is a K&N filter and Corsa catbacks. I bought it from Carmax so wasn't able to really get alot of details from the previous owner. I made a (hopeful) assumption that a 7 year old car with less than 40k when I bought it was well maintained, but I don't know.
And I agree, I had a 98 TA that got 30 mpg. That's one of the reasons that the current 22 mpg is bugging me. I know it's capable of more! Of course, the 98 was an M6...
-----
Thank you both for the quick feedback. It's appreciated!
Doing a carbon cleaning (one method is to use the top end cleaner) can't hurt and will definitely increase your mileage in a dramatic way. (If you go the do-it-yourself route, I'd recommend doing the top end cleaner. If you want to have someone else do it for you, I'd recommend having a MotorVac Carbon Clean treatment - its gets to a few more spots, but you'll have to shell out $100+ for it.) The thing is that you will need to start your mileage log all over again once you do that because you won't be comparing apples to apples.
While you are tinkering with the car, I'd also suggest doing a preemptive MAF cleaning. (There is special cleaner for the purpose at auto parts stores - other cleaners could foul the sensor.) I had some of the K&N oil shed off an contaminate my MAF. The cleaning fixed the problem - but I only run paper filters now. This issue isn't the cause of your mileage issues as it leans out the mix, but it can cause you headaches in the future.
11-24-2009, 10:32 PM
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11-24-2009, 10:59 PM
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Maybe your driving habits have changed. I know after I got my car, as I got more and more comfortable with the power of it I started driving differently (faster) and burning more gas. It has leveled off now though lol.
11-25-2009, 07:50 AM
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Ethanol does make a difference, too, but that's not what I was getting at. Google winter blend gas and see. You will have trouble finding the exact differences because it varies from place to place, but you can read about what it is and typical effects of switching to it (e.g. decreased fuel economy).
11-25-2009, 04:47 PM
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Oh I definitely enjoy flooring it, no doubt about that. But when I'm specifically tallying mileage I keep it on cruise control. I'll even let Mustangs pass me without challenge, that's how serious I am about calculating mileage!
11-25-2009, 04:49 PM
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Even though this is my second Trans Am, I'm still very much a car noob, so I'm not sure how to do this. This is something I can do myself? Or I need to have a shop do it? I can research this some more, thanks for the suggestion!
11-29-2009, 10:43 PM
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11-30-2009, 04:03 PM
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plugs, wires, coils, fuel filter to start. did you switch brands of gas? stick to shell, mobil, chevron etc... dont use mom and pop stations. do a complete engine cleaning. clean the top end with Mopar Combustion Chamber Cleaner(search for it on here). go buy a bottle of gunk engine flush and change your oil. that will clean out your bottom end. for your injectors run a can of seafoam through the tank
12-01-2009, 12:40 AM
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03-06-2010, 11:46 PM
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Thanks to the guys that answered me here... I finally got around to cleaning the MAF and running seafoam through everything. I forgot about the mopar cleaner for the top end, used seafoam on that too, have read some debates since then about mopar cleaner being better... but I'm learning...
Anyway, I've gotten my lost 4 mpg back! So I am happy. Appreciate the good advice I got here.
Anyway, I've gotten my lost 4 mpg back! So I am happy. Appreciate the good advice I got here.
