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Discussion Starter · #1 ·
I was getting 7.8 mpgs on my '88 Ford F250 2WD, reg. cab longbed. I tried STP fuel addative-that didnt work, I tried being easy on the foot-that didnt work.

Then, today, I filled up the tires to 80 psi (load range of E) and then put 87 (or whatever the middle grade of gasoline is) into the tank, then drove it on the highway and got about 9.8 mpgs.

Do you guys believe that the better gasoline helped the gas mileage? If not, what do you guys think will help me here? I mean, I have to drive this truck for about another 7 months and 7 mpgs was absolutely unacceptable. 9.8 is better, but come on.

Do you think that 91 octane gasoline will smoothen things out and make it run better? I know that in these older Fords that the people that I have talked to get the 91 octane gas because their trucks dont like the worse stuff-maybe that's the case here and my truck is just throwing a fit on me?

BTW, it has a C6 auto tranny with no overdrive (and I can guaruntee that that is one reason for such bad mileage).
 

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what size is you engine? is it fuel injected or carb.? (dont know much about fords of that year) if its fuel injected and if oyu have MAF (Mass Air Flow) sensor, clean it appropriatly with the proper parts cleaner. if its a big block then tehre may not be a whole lot you can do, espicially if it uses a carb. my personal expirience with octane is it depends on the vehicle. it made a slight diffrence in my 90 and 95 chevy and gmc half ton trucks, also had a bit more power. but not sure it would offset the price difference. but i ended up runnign mid grade anway to stop the pre-detonation at high mileage. soudns like you already ran injector/carb cleaner through. have you changed your fuel filter in the last 70k miles or so?

thats all that comes to mind at the moment... youve done really well to increase your miles by almost 3mpg. with either my 02 silverado or 05 impala the tire pressure doesnt make one bit of difference... nor does that octane rating (must be the computers in the newer models...)
 

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Pull out that slush box and stuff a stick in it, you might get up around 10-12 but i wouldnt expect more than that. Either that or get rid of it for a half ton with a manual so you have better gear ratio options. Most 3/4 tons came with 3.73 or 4.10 gears where most 1/2 tons came with 3.55's
 

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Discussion Starter · #4 ·
Its an EFI 351W.

Not sure what gears, but the only thing that it doesent have on it as far as heavy-dutyness is the fuel tank sleeves that complete the ambulance package. Otherwise, I believe that it could be an ambulance (or its setup that way).
 

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I dont think those windsors ever got real good mileage...The 80's were a dark time for engine power and performance, from all automakers...
 
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