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my 97 4.6L XR7 has 89,000mi on it......i just changed spark plugs (Bosch) and fuel filter, but not yet spark plug wires........im only gettin like 260mi a tankfull.........about 80%city/20%highway driving..........oh and i have a K&N cone filter in the fender wall where the air silencer was.........so that comes out to 260mi/18G=14.44 MPG........should i be getting better gas mileage, or is this normal for the # of miles on this car? what else should i look into?
 

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14 ain't bad, I'd like to get 14 now. City driving isn't good for milage - neither is a heavy foot ;).

OK - is your K+N clean? If it's dirty and air isn't getting through, the computer WILL substitute air with fuel. Also, your Mass Air Flow (MAF) could have an oil coating on the wires, which should be cleaned regularly with ELECTRICAL CONTACT CLEANER - NOTHING ELSE!!! Then, UNPLUG your battery terminals, as your computer won't recalibrate for the change in air/fuel mixture unless you unplug it.

Plug wires - OE wires are pretty good, and a 97's should still be in really good shape.

Other than that - I dunno :confused: .
 

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the K&N is pretty clean....i've only had it since may.....when i put it on my 97 it had very little dirt on it, so i left it as is........so when i step into my local auto parts store, do i just ask for electrical contact cleaner? does it go by a certain brand name? is it a spray?

thanks for you help
 

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guitar maestro said:
my 97 4.6L XR7 has 89,000mi on it......i just changed spark plugs (Bosch) and fuel filter, but not yet spark plug wires........im only gettin like 260mi a tankfull.........about 80%city/20%highway driving..........oh and i have a K&N cone filter in the fender wall where the air silencer was.........so that comes out to 260mi/18G=14.44 MPG........should i be getting better gas mileage, or is this normal for the # of miles on this car? what else should i look into?

Correct me if I am wrong but isnt the tank 21 gallons?

when you replaced the plugs what did you gap your plugs at?

Whens the last time you had a tune up IE PCV valve airfilter recharged?\

Are driving with the ac on?

are you pulling any codes?

I average about 18 miles per gallon but have a heavy foot.


Also a quick not you can pull fuse 15 under the hood and try yo crank the car the put the fuse back in this will reset your Computer.
 

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Re: Re: bad gas mileage.....what gives?

MadDog2020 said:
Correct me if I am wrong but isnt the tank 21 gallons?
i don't think i've ever had to fill up from Empty to full with 21 gallons......
when you replaced the plugs what did you gap your plugs at?
standard .054"
Whens the last time you had a tune up IE PCV valve airfilter recharged?\
i changed the PCV valve when i put in the new plugs......i just got my K&N cone in May.....i thought it was at least 6 months to a year before you had to service it
Are driving with the ac on?
yes always.....very hot in south texas in the summer
are you pulling any codes?
by this i assume you mean if i've changed the codes on the computer.....nope....all stock
I average about 18 miles per gallon but have a heavy foot.
if the tank is really 21 gallons that would mean my MPG would be even worse! sure hope not!
Also a quick not you can pull fuse 15 under the hood and try yo crank the car the put the fuse back in this will reset your Computer.
i'll try that too
 

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The tank is 18 gallons.

For the record I'm still holding around 24mpg after killing the violin case.
 

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guitar maestro said:
my 97 4.6L XR7 has 89,000mi on it......i just changed spark plugs (Bosch) and fuel filter, but not yet spark plug wires........im only gettin like 260mi a tankfull.........about 80%city/20%highway driving..........oh and i have a K&N cone filter in the fender wall where the air silencer was.........so that comes out to 260mi/18G=14.44 MPG........should i be getting better gas mileage, or is this normal for the # of miles on this car? what else should i look into?
I get 18-22 mpg, depending on the week...and how much weight my foot gains...
it's been rather hot around here the last week or so, so my mileage has been a bit less, but...nonetheless, i fill my tank when i see 300 miles appear on my trip odometer (sometimes more, sometimes less).


I would definitely check to make sure your MAF is clean and functioning properly. also, i would try to get the heck off city streets. stop and go driving is a pain in the ...arse .... torture on your brakes as well.

weird thing is, i think if you were to get gears, your mileage would probably go up because you do mostly city driving. in my case, however, when i get 4.10 gears, my mileage will plumet because i do much more highway driving.

...............

hope you figure out what's wrong!
good luck!

:D
 

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guitar maestro said:
the K&N is pretty clean....i've only had it since may.....when i put it on my 97 it had very little dirt on it, so i left it as is........so when i step into my local auto parts store, do i just ask for electrical contact cleaner? does it go by a certain brand name? is it a spray?

thanks for you help
Goto your local Radio Shack and look around for it. While you're @ it, get some compressed air. The compressed air can be used instead of a Q-Tip, unless you're sure that your hands wont flinch and bust the wire.
 

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Re: Re: Re: bad gas mileage.....what gives?

guitar maestro said:

yes always.....very hot in south texas in the summer
Where in TX do you live? (a little off topic...okay, completely off topic, but I'm a TX man too and just curious)
 

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Discussion Starter #11
hey brahma101, i'm from Laredo

damn i just realized i don't have those tamper resistant torx bits to take off the sensor.........can i just spray windex thru the hole where the air goes thru and then dry it with compressed air?
 

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guitar maestro said:
damn i just realized i don't have those tamper resistant torx bits to take off the sensor.........can i just spray windex thru the hole where the air goes thru and then dry it with compressed air?
That's a good question...anyone have an answer?
 

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well i ended up getting the torx bits.......there is no substitute for a good Qtip cleaning with electrical contact cleaner......what i do now is stretch the cotton off a few mm from the tip of the Qtip......and use that to rub the MAF wires........the cotton fibers soaked with electrical contact cleaner will not damage the wires unless you hand seriously flinches..........i tried dipping the MAF wires in the cleaner using a 20oz coke bottle cap, but even after 10 min........the dirt was still on there.
 

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The worest mileage I ever got was 19 MPG. I repeatedly get 23-25, 98% highway mileage but my right foot is so heavy I am always looking for a deal on decent tires. My guess is the MAF as I've replaced mine once due to drivability problems. Wasn't aware cleaning was a viable alternative, as a matter of fact i think I kept the old one. I might give it a try. What fuel do you use? I have bought 90% of my gas from one of two stations around town(BP/Amoco) and no fuel problems like some of the joints that add their own additive(water, etc). I am at 137K miles and adding about 700 per week and still going strong. One thing I have found recently during my transmission rebuild is the EPC solenoid is acting up which contributed to my bands being smoked. Are you experiecing any shifting problems?
 

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i have same problem

i have the same problem as this guy.. poor gas mileage.. new plugs, new wires, clean K&N in fenderwell, new PCV valve.. i have u/d's, been pulling the 136 code (O2 sensor circuit malfunction, bank1 sensor 2) on the d-side downstream that no one has been able to help me with or fix... i avg less than 18.5...

AND.. now the tranny starting to shift like it has a chip plugged in on moderate takeoffs. sometimes when i floor it, it shifts smooth at around 5300rpm into 2nd, then harder into 3rd and 4th when i back off as i near the speed limit..

what gives?? i thinking about getting some warranty work done to the tranny and throwing in a M8 TC, flexplate, and getting the Man-mod done all at once so i get some money back.. 97 tbird lx sport 4.6L 86,900mi

JD:confused:
 
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