Terrible milliage(sp?)

Flar

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Ive got an essentially bone stock 94 GT with 117k miles, I just replaced the wires with MSD 9.5mm Super cunducter wires, MSD Distributer cap and roter and NGK v-power spark plugs. I accidently bought 1 heat range cooler plugs then I was supposed to but the guys at JBA said it would be fine, but anyway. Im getting 120 miles out of a tank!! Thanks less then 9 MPG, this is ridiculus, I shift at around 2200 RPM and hardly ever go WOT, I bent one of the 02 sensors when I was changing out the clutch but before last week it ran alright (about 140-160 miles per tank) and the check engine light came on in 5th but once I let off the gas and went back on it would go away. Recently (in the last week when my milliage went terrible) the light would come on in 1st, and sometimes 3rd. Tomorrow I was going to go pick up new 02 sensors, a new air filter, new motorcraft plugs (right heat range, and reset the ECU, do you guys think that this will fix my milliage, or do you think it could be something else? Also, when I drive once I get out a smell gas, but when I look under the car I dont see any gas dripping and I go back and check a couple hours later and there isnt any gas on the ground, I changed the fuel filter to see if that was the problem but now the gas smell is even worse, also the car backfires sometimes at around 2500RPM but only when im in 3rd and slightly on the gas, im guessing this is because of the plugs being a heat range to cold, or could it be something more serious? So what should I do guys I cant afford to buy gas every 4 days, BTW im using 87 Octane. Thanks in advance for any help/advice!
 

Downshift

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Mileage haha. That does sound pretty bad.

What is the Check Engine light for? Like which code was it? If you don't know how to check it, there is a sticky up top.

Not sure on the plugs, but they are so cheap and easy to do I would get the correct plugs.

Do you have catalytic converters on your car or are you running an off road mid pipe? That could be a big part in you smelling gas fumes.

Bending the o2 sensor is most likely part of the problem. I could be wrong but I can see nothing but problems from that. You said you just did the clutch, are you sure you connected both the o2 sensors again?

Make sure you have the right gap when you put those new plugs in. .052 or .054 is what everyone seems to be running.

Make a list of your mods for us to. Good luck.
 

Schiffy

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damn... I thought my 150miles per tank was bad(and thats fucking around when i get bored just driving)
 
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Flar

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List of mods: King Cobra clutch, new throwout bearing/pilot bearing, new water pump, MSD cap and rotor, MSD super conductor wires, NGK V-power spark plugs (one heat range cooler), Steeda Tri-Ax short throw shifter. Thats all my mods, for now. But like I said the passenger side 02 sensor is bent and the check engine light comes on from time to time, im pretty sure that its from the 02 sensor because its only when im driving and only when I maintain an RPM, also it only started after I bent the sensor. Im running a stock H-pipe with cats and I have flowmaster mufflers with a big hole drilled in the back of the muffler next to the exit pipe to make it louder. So I was thinking, clean MAF (probably never been done and the car has 117k miles), change to correct heat range motorcraft spark plugs, and replace both 02 sensors (since they've probably never been changed either). I cant check the code because it only comes on when im driving and it just kinda comes on and off speratically.
 

topless95

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definately check to see what codes are being stored. I have a 95 GT vert and I get 20-22 mpg every single tank, and I am at 114k miles. Also have you checked tps volt. , cleaned your IAC and MAF ? They are just as important as plugs and wires. Good luck and keep us informed
 
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Flar

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Tomorrow, im going to replace both 02 sensors since they have 117k miles on them and one is bent, and I read that you are supposed to replace them every 50k miles, so its probably a good time. Im also going to change out the plugs, change the airfilter (still using an old cotton one and dont have the $ for a K&N :crying:) clean the MAF, clean the TB (anyone know what type of cleaner to use, because in my haynes it says not to clean it with carb cleaner because it will remove the protective coating, and I can definitely see carbon deposits on it so it needs to be cleaned.) And were/what is the IAC and how do I clean it? BTW, I recently changed my PCV valve with one from autozone, ane chance that could affect my mileage? It didnt seem like the most high quality peice of equipement but I didnt think it would make that much of a difference.
 

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This is a sticky posted by ryclef331 under the 94-95 section and titled fix your surging idle

Ok so the everyone who has modified their 94-95 Mustang has dreaded the idle surge from day one! My own personal stroker motor car has a chip and tune and STILL likes to surge a bit until it warms up. EITHER WAY, the principals are the SAME! I hate to link off of the site to do this but I haven't found a MORE thorough write up on how to solve your problems than this very site...PLUS it features pics of a 94-95 so it makes it MEGA easy, even for noobs!

Click here to solve your idle problems!
http://www.muscularmustangs.com/iac.php
http://www.muscularmustangs.com/iac.php

be sure to click through all the pages! the link is at the bottom of each page.

Remember this! It is imparative that you do all of the steps in the above link in order! Setting the TPS Voltage and THEN setting your idle RPM will throw the TPS Voltage right back off!
 

topless95

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I know you are not having a surging idle issue, but the steps are the same to clean and maintiain these items. :thumb:
 

topless95

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By the way, the reason I get 20-22 mpg might have to do with the fact that the 5.0 verts came w/ a 2.73 axle
 

ddrracing

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topless95 said:
By the way, the reason I get 20-22 mpg might have to do with the fact that the 5.0 verts came w/ a 2.73 axle

A little off topic, but mine came with 3.08's :dunno:
 

2slo95fiveoh

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ddrracing said:
topless95 said:
By the way, the reason I get 20-22 mpg might have to do with the fact that the 5.0 verts came w/ a 2.73 axle

A little off topic, but mine came with 3.08's :dunno:

most 5.0 cars came with 2.73, but some came with 3.08.
i dont know if this part is true, but someone told me that some rare ones
came with 3.27??
 
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Flar

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Well I changed my 02 sensors, my air filter, cleaned my MAF, TB, IAC, and ajusted my TPS, and I changed my spark plugs. Now im getting 240 miles to a take, when I bought the car I was only getting 140 to a tank, so talk about an improvement, im :banana: :dancing6: :thumb:
 

aaron427

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That is much better!! Heck with my 415rwhp 95 I was getting around 180 miles to a tank and that was mainly city with the occasional highway sprint.
 

RJayLo

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Flar said:
Well I changed my 02 sensors, my air filter, cleaned my MAF, TB, IAC, and ajusted my TPS, and I changed my spark plugs. Now im getting 240 miles to a take, when I bought the car I was only getting 140 to a tank, so talk about an improvement, im :banana: :dancing6: :thumb:

thats awesome! Just curious though, did it solve your check engine light issue? Mine is coming on intermitantly also but the only thing I have done as far as "regular maintenance" is change out the IAC.
 
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Flar

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Yea, changing the 02's got rid of the CEL, but it was weird, the 02 sensors I had were wrong and I had already taken the old ones out, so I just drove my car to autozone with the 02's out, and no CEL came on, I found it pretty odd, but once the new ones were on I that light never came on again on the freeway, and im getting much better economy.
 

2REDSTANGS

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i get about 8mpg :crying:
i have a ramdon cylinder misfire though i dont know how to fix it either....
 

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