Mileage help
05-22-2007, 10:38 PM
#1
Pro
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Mileage help
After putting a few hundred miles on my 968 swap, I've noticed that I'm getting pretty terrible gas mileage... something like 200 miles to a tank.
During the swap I installed a new 968 o2 sensor, and the car seems to be running fine power-wise (although I've never driven a 968, it's definitely faster than my 2.5 used to be.
The one thing I can think of that's not up-to-par with the rest of the engine is I'm still using my stock n/a exhaust and cat... Could a clogged cat or an exhaust that's too restrictive be causing my bad gas mileage?
Thanks
During the swap I installed a new 968 o2 sensor, and the car seems to be running fine power-wise (although I've never driven a 968, it's definitely faster than my 2.5 used to be.
The one thing I can think of that's not up-to-par with the rest of the engine is I'm still using my stock n/a exhaust and cat... Could a clogged cat or an exhaust that's too restrictive be causing my bad gas mileage?
Thanks
05-22-2007, 11:10 PM
#4
Three Wheelin'
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I find that spirited driving tosses the mileage straight down the freaking toilet. The handy-dandy mileage gauge, assuming it's accurate, reveals the fugly truth of it.
Though a bad exhaust will hurt too. And have you checked the air filter?
Though a bad exhaust will hurt too. And have you checked the air filter?
05-23-2007, 03:37 AM
#7
Burning Brakes
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Wow. I just filled up today and I ran 200miles on a half tank. All of which was city driving + 2 street chases. 17mpg right on the factory estimate. That is low for me because I usually get 19-20 
. Darn those mustangs, always makin me chase them.
. Darn those mustangs, always makin me chase them.
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05-23-2007, 05:31 AM
#8
A 968 should get 25/30MPG cruising the highway at a steady pace (60/75mph) and good gas (not that blended crap) 
,NOW if you put your foot into it; that number drops to somewhere south of 10MPG 
. But I say "F" it, didn't buy the car for MPG. I got it for SPC "smiles per curve" 
,NOW if you put your foot into it; that number drops to somewhere south of 10MPG . But I say "F" it, didn't buy the car for MPG. I got it for SPC "smiles per curve"
05-23-2007, 12:43 PM
#11
Captain Obvious
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I went to Ottawa 2 weeks ago (6 hours each way) and got 31 mpg using 91 octane "supreme" gas.
I'd say a clogged cat...its still the one from the original I'll bet.
I'd say a clogged cat...its still the one from the original I'll bet.
05-23-2007, 01:01 PM
#12
Race Car
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As a reference point, I'm using a stock n/a exhaust mated to a 968 motor -- I get about 24mpg on the highway (cruising at 80mph). You can also expect to get worse mileage than the 968 because of the gearing in your tranny. I'm using an 944S tranny, which has shorter 5th gear -- so I'm close to 4000rpm when I'm cruising at 80mph.
I'd also check to see if the O2 sensor is properly hooked up on the harness side.
I'd also check to see if the O2 sensor is properly hooked up on the harness side.
05-23-2007, 03:21 PM
#15
Captain Obvious
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I dunno on smell, but a clogged cat will heat up too....I had a Fiero GT with a clogged cat and the power was way down and it sounds muffled. The cat was glowing red. (worst case scenario I'd assume)
I'd check the O2 sensor too as stated.
I'd check the O2 sensor too as stated.