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Discussion Starter #1
My 2013 F-150 5.0 4x4 gas mileage dropped from 16.5 to 11.4 ???? New Mallory cats new plugs motor craft New fuel pump new water pump all in the last 3 mouths. Help
 

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Discussion Starter #5
It not running ruff at idle or at speed . Some times it starts right up other times it goes almost to the end of the crank cycle someone told me that if you disconnect the battery you might have to go to FORD to get it reset ??
 

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Is that air filter oiled by chance? K&n oiled air filters are known to contaminate maf sensors causing issues.


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Discussion Starter #8
Yes it's a k&n filter it's been in for just over 30,000 issues just started about about 2,500miles ago doesn't need re oiled for another 70,000
 

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Have you cleaned your maf? Checked tire pressure and alignment?


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Theres maf specific cleaner, thats all I’d recommend. Otherwise have you been doing anything different or going to a different gas station around when this began?


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All of the above comments apply, but here's clue number 1:
"And if you stand on it it will set you back in the seat hard". My mileage drops drastically when I "put my foot in it" or when I loan a car to my son. But what good is horsepower if not to enjoy from time to time? BTW, you will not have to go to the dealer when you disconnect your batt, just give the ECM a little time to relearn your engine and transmission settings.
 

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Discussion Starter #16
It's been a month and a half at 73 miles a day . Like I said when I stand on it it doesn't ask how Hi it just clears the moon. Jwk I believe you have loss in the colder weather also but not this much. If I am a good boy the milage is down 5
 

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Do you have the means of measuring your fuel trim? You say it will sit you back into the seat, if it seems to be more aggressive, you may be burning richer. Not sure if it'd kill your gas mileage by that much, but it's a start.
 

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Discussion Starter #18
If you ask me to adjust a 650 Holly double pumper no problem. I will look around see if I can find someone with that equipment May have to take it to Ford TY
 

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why the new cats?

K&N oil may have fouled the MAF and the 0-2's

if the cats are high flow, there may be your answer, reduce back-pressure will put a hit on mpg. i just removed some glass packs and returned the stock mufflers and gained from around 12 back to almost 18 from my 150k 4.6

also, a battery disconnect may trigger a re-cal that might correct your fuel trim map
 

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Discussion Starter #20
Ty . I also remove the resanater .any idea how to restore the back pressure . I'm thinking put a much smaller pipe where the resanater was ??
 
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