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Mar 5, 2003 | 05:52 PM

andy231v6

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mpg loss

I have a 2000 f-350 king cab 8 foot bed dually with auto trans I use for work. I have notice for a while bad gas numbers. MPG has gone from 14 and some change to 11 and change. A couple things I have noticed latley at certin light throttle positions I hear an air escaping noise like a hiss (not turbo hiss) if I give more throttle or less it goes away. Also even if the truck is at running temp if I let it idle for any length of time the engine rpm rises I do not know if this is normal. I have done all the regular maint. oil, air ,fuell. Also chip has been reprogramed with superchips microtuner 2001 bet I did that a long time before this problem. Sorry for long post and thank you for any suggestions you might have. Andy

Mar 5, 2003 | 07:17 PM

alanscott

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From: Western Colorado USA

mpg loss

First suggestion would be to not put "Gas" in it, since it's a diesel

Second, it's normal to lose milage in the winter because of the way the refineries winterize the fuel.

This thread covers it, any other questions, just jump in.
https://www.ford-trucks.com/forums/s...threadid=95778

Welcome to the site!

Mar 5, 2003 | 08:27 PM

Quadzilla

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From: Bonney Lake, WA

mpg loss

The hissing you're hearing is your Exhaust BackPressure Valve, or EBPV in operation. It's a butterfly valve immediately downstream from the turbo, which closes to allow the engine to warm up faster. It will also cycle when the ambient temperature outside is below 50*, regardless of engine temperature. It's considered normal for it to do that, and it might be that you just haven't noticed it before because of a change in weather, or have been listening more closely, trying to determine why your mileage has dropped. I typically see a 2mpg drop during the winter, but it rebounds nicely in the spring. If fuel prices continue to rise, that'll be a welcome sight.

Mar 5, 2003 | 08:55 PM

alanscott

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mpg loss

Quote:

Originally posted by Quadzilla
If fuel prices continue to rise, that'll be a welcome sight.

Well said.

Mar 5, 2003 | 10:20 PM

andy231v6

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mpg loss

Thanks for your input Quad the butterfly valve makes sense because it does not do it all the time. I guess I will wait for warm weather and hope milage comes back. Andy

Mar 5, 2003 | 11:37 PM

JoeBoost

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From: C H I C A G O

mpg loss

ANDY -
My truck looses major MPG going from summer to winter diesel , along with the more stop and go driving i do avoiding idiot chicago drivers who act like they have never seen snow before.

I have kept a log of my weekely average MPG sience the first of the year , and when it warms up i will compare, but just like last spring the numbers should rise some...

Mar 6, 2003 | 04:56 AM

Quadzilla

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From: Bonney Lake, WA

mpg loss

I started keeping a log of fuel mileage in 2/02, so I can compare my mileage to the same month last year, and to see if the mods I've done have any impact on mileage. Though my mileage has dropped as a result of winter fuel, I'm still doing better than last year: 2/02- 13.5 mpg; 2/03- 15.5 mpg.