Gas mileage drop off
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Do you have any codes set? Please check and let us know what they are. If the intake ducting between the throttle body isnt sealed properly, it will cause symptoms like that and set codes.
BC
BC
Le Mans Master
Joined: Jan 2002
Posts: 5,892
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From: Ft. Myers FL
I found from my own experience that when I put on a LS6 intake and a Vararam my car started running rich. Believe it or not, I ran in the high 12.5's & 12.6's and now I only get to the low 12.7's. 
Wierd, huh. ;yn
Wierd, huh. ;yn
Instructor
Joined: Jan 2005
Posts: 190
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Originally Posted by Bill Curlee
Do you have any codes set? Please check and let us know what they are. If the intake ducting between the throttle body isnt sealed properly, it will cause symptoms like that and set codes.
BC
BC
Are you talking about the accordian tube? If so I need to probably check that.
I put the TBYRNE MAF ends on, put on the Vararam with the K&N, and put new NGK Tr55's (orignally had Iridiums in it) and I lost about 2 mpg myself. I don't drive it hard so I know it was the mods. Weird though.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I just had my car dyno tuned and Mike (Tuner) stated that my AFR's were all whacked out. The MAF wasn't registering all the air going through it! I was running LEAN, the computer was dumping all the extra fuel in that it could to richen it up but was having trouble keeping up! It was pulling A$$ loads of timing and had a lot of Knock.
A few strokes of the computer key board and some dyno pulls and every thing is back to normal and I have 20+ HP to boot!
If you screw with your intake system, it is a wise thing to get it tuned to optomize the combination. Especialy if you lose power of loose fuel efficiency! I went from 28-30 highway all the way down to 20-23! I knew I had a tuning problem!!!!
Im back up to 25-28 and it is still learning.
Bill
It was pulling A$$ loads of timing and had a lot of Knock.A few strokes of the computer key board and some dyno pulls and every thing is back to normal and I have 20+ HP to boot!
If you screw with your intake system, it is a wise thing to get it tuned to optomize the combination. Especialy if you lose power of loose fuel efficiency! I went from 28-30 highway all the way down to 20-23! I knew I had a tuning problem!!!!
Im back up to 25-28 and it is still learning.
Bill
Team Owner
Joined: May 2001
Posts: 36,836
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Originally Posted by 01vetteC5
are you sure your just not drivng a little faster with teh new mods lol that could be it- i have a average of like 15 mpg lol 
i need to slow down 
i need to slow down Yup. It's a well known fact that excessive "tweaking" of the right ankle has a detrimental effect on your mpg.
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Pro
Joined: Nov 2004
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From: Thousand Oaks CA
Originally Posted by Bill Curlee
I just had my car dyno tuned and Mike (Tuner) stated that my AFR's were all whacked out. The MAF wasn't registering all the air going through it! I was running LEAN, the computer was dumping all the extra fuel in that it could to richen it up but was having trouble keeping up! It was pulling A$$ loads of timing and had a lot of Knock.
A few strokes of the computer key board and some dyno pulls and every thing is back to normal and I have 20+ HP to boot!
If you screw with your intake system, it is a wise thing to get it tuned to optomize the combination. Especialy if you lose power of loose fuel efficiency! I went from 28-30 highway all the way down to 20-23! I knew I had a tuning problem!!!!
Im back up to 25-28 and it is still learning.
Bill
It was pulling A$$ loads of timing and had a lot of Knock.A few strokes of the computer key board and some dyno pulls and every thing is back to normal and I have 20+ HP to boot!
If you screw with your intake system, it is a wise thing to get it tuned to optomize the combination. Especialy if you lose power of loose fuel efficiency! I went from 28-30 highway all the way down to 20-23! I knew I had a tuning problem!!!!
Im back up to 25-28 and it is still learning.
Bill
Le Mans Master
Joined: Nov 2003
Posts: 8,004
Likes: 250
From: Tampa Fl
St. Jude Donor '12-'13-'14
Originally Posted by LoneStarFRC
Yup. It's a well known fact that excessive "tweaking" of the right ankle has a detrimental effect on your mpg.
Althought, after my tune I got better highway cruising gas mileage. It was 32-33 MPG at 75-80 MPH.
Around town, I seemed to lose a little mileage. Issues with the right foot thing
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Originally Posted by cop.magnet.red
I gotta move near a "car guy". I'm getting 19 - 20 and I thought that was good 
If your low MPG figures are not being caused by mods, reexamine all of the things that can cause poor milage. Check the air filter, proper air pressure in the tires, check for codes, and last but not least,,,if you are heavy on the right foot your mileage figures will always suffer. I also shift in to high gear as soon as possible once I'm up to speed.
Steady state crusing speeds should click of 25-30 mpg easily.
BC
Instructor
Joined: Jan 2005
Posts: 190
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Hmm I am sure I should be getting better but I don't really have to many mods. What should a '99 A4 with a Vararam, TR55's and TBYRNE MAF ends be getting in town. I'm only getting 18 mpg. I was at 20 mpg before I did some mods. I put the stock MAF back on and it didn't change anything. I would assume the Vararam would hurt anything because it is in front of the MAF. Could running TR55's hurt gas milage? I had the iridiums in there before. I just changed them because I had just bought the car and it had 34k on them.
