V6 (1994-2004) Mustangs Technical discussions on the 3.8L and 3.9L V6 torque monsters

Terrible gas mileage

Old 10-24-2010, 11:23 AM
  #11  
Matt's 95 Stang
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Originally Posted by Synyster06Gates
+1. Even with my cam and other mods, extremely heavy right foot I still manage about 17 city 25 highway (at 80)

Replace your plugs and wires, especially if you don't know the last time they were done.


Also, don't forget to check your blinker fluid and muffler bearings, I heard they can drop your mpgs.

EDIT: 1000th post!
I know what you mean. After I replaced my blinker fluid I gained HP and MPG!!! And my car now sounds like a V8 after replacing the muffler bearings...
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Old 10-26-2010, 07:14 AM
  #12  
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could it have anything to do with a cracked manifold?!
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Old 10-26-2010, 07:30 AM
  #13  
brent4
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Yes it could. If the manifold was cracked you'd hear/smell an exhaust leak.
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Old 10-27-2010, 08:07 PM
  #14  
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my manifold is cracked, but the only thing i hear is a slight ticking when it starts up and it goes away after like 15 seconds.
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Old 10-27-2010, 08:16 PM
  #15  
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btw VERY FUNNY Synyster06Gates..
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Old 10-27-2010, 08:19 PM
  #16  
MustangSally94
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If the manifold is cracked your going to lose MPG's. If you get that fixed and replace your plugs and wires and maybe get your injectors cleaned that should fix your problem
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Old 10-27-2010, 08:55 PM
  #17  
WoahPony
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I bought my car with 72k Miles. I was getting a mixed average of ~17-20 MPG... I had a manifold leak, my plugs and wires had never been changed, original battery, and what I'm assuming to be dirty injectors. within 3000 miles I replaced plugs, wires, battery, fuel filter, swapped to K&N drop in filter, LT headers to fix the leak. swapped to Mobil 1 full synthetic, used Zmax fuel and oil cleaner, seafoamed engine and topped it off with a 93 octane economy tune. On my automatic I was seeing over 30 mpg with mostly highway driving
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Old 10-28-2010, 09:56 AM
  #18  
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I had my muffler bearings replaced a while back. Was only $300, but the car runs so much better now. Think I gained 10-15hp, too, with the aftermarket bearings.
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Old 11-03-2010, 12:37 AM
  #19  
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i get 28-30 mpg highway with 3.73s X_X do a tune up, fix the exhaust manifold. it may be a good idea to change your o2 sensors also. i changed mine after i did my longtubes and i noticed better mpg
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