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What does everyone with the 4.6 get for gas mileage? I am getting about 15 in town, if that.

Anyone know how I can boost it.... with out buying a Prius? :D
 

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seafoam it, and check the tire psi.
 

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Drive it like there is a glass of acid sitting in the front seat. :D

The 4.6L is only rated at 16 City and 23 Highway, so you're really not too far off.

But of course do all the normal tuneup things and make sure your MAF is clean. Then you can get more creative and change rear end ratio's, get a tune for fuel economy (sadly only worth about 1mpg on the early MN12's), etc.

The number one thing that lowers fuel economy is the user attached to the gas pedal. :beek:
 

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Make sure your plugs and wires are in good shape. Replace any broken or cracked vacuum lines. Clean the MAF if you haven't done so. Change the fuel filter and air filter if it's been a while. Change the front O2 sensors if they have high mileage. Check your tire pressure and alignment. And seafoam the engine.
 

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Ironically my mpg increased significantly when I replaced my square airbox with an '01 GT round airbox w/my stock maf. I just modified a maf adapter.
 

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Really, did you do a thread on how you did it? Me and my buddy deal mostly with the 94-95 V8 MN12's and this would be very useful information.
 

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He said he was using the stock MAF.
 

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Just an FYI, doing what was stated above will cost about $600. Figure the following:

GT MAF & Airbox - $185
Pigtail - $25
Tune - $400

There are much cheaper things to be done that changing the MAF, and it will take a while for a ROI.
HELL NO! Maybe a misunderstanding..my set up cost me like $10.00 off ebay. Airbox + the tube (which I didn't use).

I simply adapted the GT airbox to my 100% stock maf + stock tube. I will take some pictures if you would like.

Reaper: Maybe I could do a new thread. Don't want to post useless info, but I think this setup looks and performs nice!
 

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Well I know at least 2 people who would like this info. and does it really cost $400 for a dyno tune?
 

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HELL NO! Maybe a misunderstanding..my set up cost me like $10.00 off ebay. Airbox + the tube (which I didn't use).

I simply adapted the GT airbox to my 100% stock maf + stock tube. I will take some pictures if you would like.

Reaper: Maybe I could do a new thread. Don't want to post useless info, but I think this setup looks and performs nice!
it most definitely is a misunderstanding......master486 was talking about using a mustang GT airbox AND the 80mm GT MAF.....to use this you'd need a pcm tune to account for the different airflow/voltage calibration differences in MAFs...and to electrically connect the whole thing into a 94/95, well, you can't...thats is why you need the pigtail harness......because the connector is a different shape

that said, Jestkdn, once you do normal maintenance on your car, the only way you can boost it is to accelerate at a slower rate ......if its not enough, and you mostly want in-city fuel economy to rise, then you can look into shorter gears with a complementing tune for them and fuel economy......18+ would not be impossible with the right tune
 

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Ok well my car is upgraded now I did a Pi conversion on stock 97 block. StageII Crower cams and upgraded springs. 3.73 rear with duals, underdrives, a 01 Gt airbox and upgraded MAf and an SCT Tune. Before it would vary with the PI upgrade it actually went up to more consistant 20-21.5 MPG so im happy with that. Considering it is 250 some horse now its putting out so. All can be nice, just depends on many factors.
Regg
 

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I'm getting 28 to 29 MPG Combined.

Only thing that is changed from the mods in my sig is that I've got a Stock EEC, Stock MAF, stock airbox with a K&N Panel filter, Air silencer removed, and the 2.73's.

I do a little more freeway driving, but I'm still just under 29 MPG without a custom tune. I'm planning on seeing what kind of tune I can get to lean things out a little more. I'd like to be in the 30's with this set-up. I may have the shift points adjusted a little bit as well.

I try and keep my shifts at or below 2K. I cruise at around 72 MPH at about 1700 RPM. My low end torque isn't there like with the 3.73's obviously, but I'm not trying to race the world here either.
 

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the most the EEC can lean it out is to 15.1:1 under closed loop operation.......to get to the ideal 15.4:1 lean cruise ratio, you'd have to go open loop under those conditions (O2s simply will not allow any more than 15.1:1)...that said, i've read that it isnt really worth all the trouble....you might see 2% more fuel economy......besides, im pretty sure he is more worried about city fuel economy rather than hwy, as i'm pretty sure it is his daily driver, or he wouldnt be asking about gas mileage lol
 

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Now since I have O2 deletes...I wonder if I can do any better?
 

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Yes, I misunderstood what 96dirtybird said he had done. Sorry for the confusion.

Now since I have O2 deletes...I wonder if I can do any better?
I'm assuming you have deletes for the rear sensors in which case it doesn't matter, as those have nothing to do with the fuel trim functionality in the ECM. If you have those for the fronts...I wouldn't do that.
 

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I'm assuming you have deletes for the rear sensors in which case it doesn't matter, as those have nothing to do with the fuel trim functionality in the ECM. If you have those for the fronts...I wouldn't do that.
No deletes for the front....just the rear;)
 

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If you have other issues it impacts the gas mileage...

Doing these things raised my gas mileage a bit...

Replacing transmission (Duhuh... :rolleyes:)
Replacing O2 sensors
Fixing bad vacuum lines
Cleaning MAF
Replacing plugs/wires
Cleaning out my O2 deletes, (as they were shorting out one side of the whole O2 system) and casting them in high temperature RTV
Replacing the Diff with a 3.08 (originally a 3.27)
Replacing the tires (same brand, just 3 years newer)
Replacing the IAC
Seafoaming the engine
Replacing the Brake Booster (also fixed an intermittent lean condition Check Engine light)

This is pretty much a list of almost everything I've ever had to replace on either car, and each problem showed up in the mileage first. (I've tracked every tankful for the last 6+years)

Adding 40 pounds of stereo equipment dropped the long term average 1 mpg, which is currently 26.4 mpg; it was 28 but the gas went to crap this spring. :(

Neither of my cars like ethanol in the mix, at any percentage. There is still one Exxon station here that has real gas; I hope it lasts...

I always run premium, and drive ~120 miles per day to work and back; all interstate but about 3 miles at each end, so hitting these numbers will be hard to do.

But I have one week in the data where I ended up following a Trooper all the way to work for a week, and got 34+mpg. (on one tank...It's so hard to keep my foot off the throttle... :) )
 
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