sudden gas mileage drop
02-10-2006 | 07:44 AM
#1
Guest
Posts: n/a
sudden gas mileage drop
I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
smooth, more-or-less quietly, and with normal acceleration, but in the
last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
down to 18-19 mpg. What should I be looking for as the culprit?
This mileage drop started during warm weather (40s), so I can't blame
it on cold temps, and my tires are inflated properly. The car is a
MT, also, but I'm the only driver for the most part. Suggestions?
smooth, more-or-less quietly, and with normal acceleration, but in the
last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
down to 18-19 mpg. What should I be looking for as the culprit?
This mileage drop started during warm weather (40s), so I can't blame
it on cold temps, and my tires are inflated properly. The car is a
MT, also, but I'm the only driver for the most part. Suggestions?
02-10-2006 | 08:08 AM
#2
Guest
Posts: n/a
Re: sudden gas mileage drop
"KLS" <xymergy@suds.com> wrote in message
news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com...
> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
> smooth, more-or-less quietly, and with normal acceleration, but in the
> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
> down to 18-19 mpg. What should I be looking for as the culprit?
>
> This mileage drop started during warm weather (40s), so I can't blame
> it on cold temps, and my tires are inflated properly. The car is a
> MT, also, but I'm the only driver for the most part. Suggestions?
Is your water temperature right? A bad T'stat will cause low running temps
will cause the ECU to overfuel the car.
I.
02-10-2006 | 08:08 AM
#3
Guest
Posts: n/a
Re: sudden gas mileage drop
"KLS" <xymergy@suds.com> wrote in message
news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com...
> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
> smooth, more-or-less quietly, and with normal acceleration, but in the
> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
> down to 18-19 mpg. What should I be looking for as the culprit?
>
> This mileage drop started during warm weather (40s), so I can't blame
> it on cold temps, and my tires are inflated properly. The car is a
> MT, also, but I'm the only driver for the most part. Suggestions?
Is your water temperature right? A bad T'stat will cause low running temps
will cause the ECU to overfuel the car.
I.
02-10-2006 | 08:08 AM
#4
Guest
Posts: n/a
Re: sudden gas mileage drop
"KLS" <xymergy@suds.com> wrote in message
news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com...
> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
> smooth, more-or-less quietly, and with normal acceleration, but in the
> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
> down to 18-19 mpg. What should I be looking for as the culprit?
>
> This mileage drop started during warm weather (40s), so I can't blame
> it on cold temps, and my tires are inflated properly. The car is a
> MT, also, but I'm the only driver for the most part. Suggestions?
Is your water temperature right? A bad T'stat will cause low running temps
will cause the ECU to overfuel the car.
I.
02-10-2006 | 08:23 AM
#5
Guest
Posts: n/a
Re: sudden gas mileage drop
On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>"KLS" <xymergy@suds.com> wrote in message
>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com.. .
>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>> smooth, more-or-less quietly, and with normal acceleration, but in the
>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>> down to 18-19 mpg. What should I be looking for as the culprit?
>>
>> This mileage drop started during warm weather (40s), so I can't blame
>> it on cold temps, and my tires are inflated properly. The car is a
>> MT, also, but I'm the only driver for the most part. Suggestions?
>
>Is your water temperature right? A bad T'stat will cause low running temps
>will cause the ECU to overfuel the car.
Water temp seems fine, always reads at the noon hash mark, sometimes
wanders up to the next hash mark (the pattern for this particular
T-stat, which was put in at 69k miles during the TB/water pump
changeout). No change in behavior there. Should I get this tested
anyway?
>
>"KLS" <xymergy@suds.com> wrote in message
>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com.. .
>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>> smooth, more-or-less quietly, and with normal acceleration, but in the
>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>> down to 18-19 mpg. What should I be looking for as the culprit?
>>
>> This mileage drop started during warm weather (40s), so I can't blame
>> it on cold temps, and my tires are inflated properly. The car is a
>> MT, also, but I'm the only driver for the most part. Suggestions?
>
>Is your water temperature right? A bad T'stat will cause low running temps
>will cause the ECU to overfuel the car.
Water temp seems fine, always reads at the noon hash mark, sometimes
wanders up to the next hash mark (the pattern for this particular
T-stat, which was put in at 69k miles during the TB/water pump
changeout). No change in behavior there. Should I get this tested
anyway?
02-10-2006 | 08:23 AM
#6
Guest
Posts: n/a
Re: sudden gas mileage drop
On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>"KLS" <xymergy@suds.com> wrote in message
>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com.. .
>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>> smooth, more-or-less quietly, and with normal acceleration, but in the
>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>> down to 18-19 mpg. What should I be looking for as the culprit?
>>
>> This mileage drop started during warm weather (40s), so I can't blame
>> it on cold temps, and my tires are inflated properly. The car is a
>> MT, also, but I'm the only driver for the most part. Suggestions?
>
>Is your water temperature right? A bad T'stat will cause low running temps
>will cause the ECU to overfuel the car.
Water temp seems fine, always reads at the noon hash mark, sometimes
wanders up to the next hash mark (the pattern for this particular
T-stat, which was put in at 69k miles during the TB/water pump
changeout). No change in behavior there. Should I get this tested
anyway?
>
>"KLS" <xymergy@suds.com> wrote in message
>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com.. .
>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>> smooth, more-or-less quietly, and with normal acceleration, but in the
>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>> down to 18-19 mpg. What should I be looking for as the culprit?
>>
>> This mileage drop started during warm weather (40s), so I can't blame
>> it on cold temps, and my tires are inflated properly. The car is a
>> MT, also, but I'm the only driver for the most part. Suggestions?
>
>Is your water temperature right? A bad T'stat will cause low running temps
>will cause the ECU to overfuel the car.
Water temp seems fine, always reads at the noon hash mark, sometimes
wanders up to the next hash mark (the pattern for this particular
T-stat, which was put in at 69k miles during the TB/water pump
changeout). No change in behavior there. Should I get this tested
anyway?
02-10-2006 | 08:23 AM
#7
Guest
Posts: n/a
Re: sudden gas mileage drop
On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>"KLS" <xymergy@suds.com> wrote in message
>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com.. .
>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>> smooth, more-or-less quietly, and with normal acceleration, but in the
>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>> down to 18-19 mpg. What should I be looking for as the culprit?
>>
>> This mileage drop started during warm weather (40s), so I can't blame
>> it on cold temps, and my tires are inflated properly. The car is a
>> MT, also, but I'm the only driver for the most part. Suggestions?
>
>Is your water temperature right? A bad T'stat will cause low running temps
>will cause the ECU to overfuel the car.
Water temp seems fine, always reads at the noon hash mark, sometimes
wanders up to the next hash mark (the pattern for this particular
T-stat, which was put in at 69k miles during the TB/water pump
changeout). No change in behavior there. Should I get this tested
anyway?
>
>"KLS" <xymergy@suds.com> wrote in message
>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com.. .
>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>> smooth, more-or-less quietly, and with normal acceleration, but in the
>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>> down to 18-19 mpg. What should I be looking for as the culprit?
>>
>> This mileage drop started during warm weather (40s), so I can't blame
>> it on cold temps, and my tires are inflated properly. The car is a
>> MT, also, but I'm the only driver for the most part. Suggestions?
>
>Is your water temperature right? A bad T'stat will cause low running temps
>will cause the ECU to overfuel the car.
Water temp seems fine, always reads at the noon hash mark, sometimes
wanders up to the next hash mark (the pattern for this particular
T-stat, which was put in at 69k miles during the TB/water pump
changeout). No change in behavior there. Should I get this tested
anyway?
02-10-2006 | 10:23 AM
#8
Guest
Posts: n/a
Re: sudden gas mileage drop
KLS,
I'd check the mass airflow sensor and the oxygen sensor(s). You can do so
without removing them using an voltmeter that has a "duty cycle" setting.
I'm sure you could get the specs from the A4 newsgroup on Audiworld.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)
"KLS" <xymergy@suds.com> wrote in message
news:t34pu118mnufe4mtnbhmd2on0uuo4gkvgb@4ax.com...
> On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>>
>>"KLS" <xymergy@suds.com> wrote in message
>>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com. ..
>>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>>> smooth, more-or-less quietly, and with normal acceleration, but in the
>>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>>> down to 18-19 mpg. What should I be looking for as the culprit?
>>>
>>> This mileage drop started during warm weather (40s), so I can't blame
>>> it on cold temps, and my tires are inflated properly. The car is a
>>> MT, also, but I'm the only driver for the most part. Suggestions?
>>
>>Is your water temperature right? A bad T'stat will cause low running
>>temps
>>will cause the ECU to overfuel the car.
>
> Water temp seems fine, always reads at the noon hash mark, sometimes
> wanders up to the next hash mark (the pattern for this particular
> T-stat, which was put in at 69k miles during the TB/water pump
> changeout). No change in behavior there. Should I get this tested
> anyway?
I'd check the mass airflow sensor and the oxygen sensor(s). You can do so
without removing them using an voltmeter that has a "duty cycle" setting.
I'm sure you could get the specs from the A4 newsgroup on Audiworld.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)
"KLS" <xymergy@suds.com> wrote in message
news:t34pu118mnufe4mtnbhmd2on0uuo4gkvgb@4ax.com...
> On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>>
>>"KLS" <xymergy@suds.com> wrote in message
>>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com. ..
>>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>>> smooth, more-or-less quietly, and with normal acceleration, but in the
>>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>>> down to 18-19 mpg. What should I be looking for as the culprit?
>>>
>>> This mileage drop started during warm weather (40s), so I can't blame
>>> it on cold temps, and my tires are inflated properly. The car is a
>>> MT, also, but I'm the only driver for the most part. Suggestions?
>>
>>Is your water temperature right? A bad T'stat will cause low running
>>temps
>>will cause the ECU to overfuel the car.
>
> Water temp seems fine, always reads at the noon hash mark, sometimes
> wanders up to the next hash mark (the pattern for this particular
> T-stat, which was put in at 69k miles during the TB/water pump
> changeout). No change in behavior there. Should I get this tested
> anyway?
02-10-2006 | 10:23 AM
#9
Guest
Posts: n/a
Re: sudden gas mileage drop
KLS,
I'd check the mass airflow sensor and the oxygen sensor(s). You can do so
without removing them using an voltmeter that has a "duty cycle" setting.
I'm sure you could get the specs from the A4 newsgroup on Audiworld.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)
"KLS" <xymergy@suds.com> wrote in message
news:t34pu118mnufe4mtnbhmd2on0uuo4gkvgb@4ax.com...
> On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>>
>>"KLS" <xymergy@suds.com> wrote in message
>>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com. ..
>>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>>> smooth, more-or-less quietly, and with normal acceleration, but in the
>>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>>> down to 18-19 mpg. What should I be looking for as the culprit?
>>>
>>> This mileage drop started during warm weather (40s), so I can't blame
>>> it on cold temps, and my tires are inflated properly. The car is a
>>> MT, also, but I'm the only driver for the most part. Suggestions?
>>
>>Is your water temperature right? A bad T'stat will cause low running
>>temps
>>will cause the ECU to overfuel the car.
>
> Water temp seems fine, always reads at the noon hash mark, sometimes
> wanders up to the next hash mark (the pattern for this particular
> T-stat, which was put in at 69k miles during the TB/water pump
> changeout). No change in behavior there. Should I get this tested
> anyway?
I'd check the mass airflow sensor and the oxygen sensor(s). You can do so
without removing them using an voltmeter that has a "duty cycle" setting.
I'm sure you could get the specs from the A4 newsgroup on Audiworld.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)
"KLS" <xymergy@suds.com> wrote in message
news:t34pu118mnufe4mtnbhmd2on0uuo4gkvgb@4ax.com...
> On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>>
>>"KLS" <xymergy@suds.com> wrote in message
>>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com. ..
>>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>>> smooth, more-or-less quietly, and with normal acceleration, but in the
>>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>>> down to 18-19 mpg. What should I be looking for as the culprit?
>>>
>>> This mileage drop started during warm weather (40s), so I can't blame
>>> it on cold temps, and my tires are inflated properly. The car is a
>>> MT, also, but I'm the only driver for the most part. Suggestions?
>>
>>Is your water temperature right? A bad T'stat will cause low running
>>temps
>>will cause the ECU to overfuel the car.
>
> Water temp seems fine, always reads at the noon hash mark, sometimes
> wanders up to the next hash mark (the pattern for this particular
> T-stat, which was put in at 69k miles during the TB/water pump
> changeout). No change in behavior there. Should I get this tested
> anyway?
02-10-2006 | 10:23 AM
#10
Guest
Posts: n/a
Re: sudden gas mileage drop
KLS,
I'd check the mass airflow sensor and the oxygen sensor(s). You can do so
without removing them using an voltmeter that has a "duty cycle" setting.
I'm sure you could get the specs from the A4 newsgroup on Audiworld.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)
"KLS" <xymergy@suds.com> wrote in message
news:t34pu118mnufe4mtnbhmd2on0uuo4gkvgb@4ax.com...
> On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>>
>>"KLS" <xymergy@suds.com> wrote in message
>>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com. ..
>>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>>> smooth, more-or-less quietly, and with normal acceleration, but in the
>>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>>> down to 18-19 mpg. What should I be looking for as the culprit?
>>>
>>> This mileage drop started during warm weather (40s), so I can't blame
>>> it on cold temps, and my tires are inflated properly. The car is a
>>> MT, also, but I'm the only driver for the most part. Suggestions?
>>
>>Is your water temperature right? A bad T'stat will cause low running
>>temps
>>will cause the ECU to overfuel the car.
>
> Water temp seems fine, always reads at the noon hash mark, sometimes
> wanders up to the next hash mark (the pattern for this particular
> T-stat, which was put in at 69k miles during the TB/water pump
> changeout). No change in behavior there. Should I get this tested
> anyway?
I'd check the mass airflow sensor and the oxygen sensor(s). You can do so
without removing them using an voltmeter that has a "duty cycle" setting.
I'm sure you could get the specs from the A4 newsgroup on Audiworld.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
(SPAM Blocker NOTE: Remove SHOES to reply)
"KLS" <xymergy@suds.com> wrote in message
news:t34pu118mnufe4mtnbhmd2on0uuo4gkvgb@4ax.com...
> On Fri, 10 Feb 2006 13:08:20 GMT, "Iain Miller" <donot@spam.me> wrote:
>
>>
>>"KLS" <xymergy@suds.com> wrote in message
>>news:e71pu1tmkibqggdiscitdqte7m9tr6gu6p@4ax.com. ..
>>> I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great,
>>> smooth, more-or-less quietly, and with normal acceleration, but in the
>>> last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg
>>> down to 18-19 mpg. What should I be looking for as the culprit?
>>>
>>> This mileage drop started during warm weather (40s), so I can't blame
>>> it on cold temps, and my tires are inflated properly. The car is a
>>> MT, also, but I'm the only driver for the most part. Suggestions?
>>
>>Is your water temperature right? A bad T'stat will cause low running
>>temps
>>will cause the ECU to overfuel the car.
>
> Water temp seems fine, always reads at the noon hash mark, sometimes
> wanders up to the next hash mark (the pattern for this particular
> T-stat, which was put in at 69k miles during the TB/water pump
> changeout). No change in behavior there. Should I get this tested
> anyway?
