Horrible fuel mileage on e99

[hollister25073]

A friend of mine has an early 99 7.3 auto eclb no lift all stock except gauges his fuel mileage dropped to about 9.8-10.5 mpg in the last couple weeks my cclb with 35's and tunes can get 18 freeway

Now we changed every filter fresh oil all that stuff no codes are being thrown but anybody know where to start with this problem


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[White7.3stroker]

Sliders on his brakes may not be releasing? Its a idea i dont know if it helps or not

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[hollister25073]

He just did all his brakes not long ago because a caliper did hang out but it's a place to start


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[400kStroker]

When I had a bad milage issue a few years back it was the turbo. The prop bearing was pretty much shot, so there was hardly no boost and it was taking 1800-2000 rpm before the turbo would even begin to spool up. The engine would compensate by dumping more fuel. After I rebuilt the turbo, my economy literally doubled on highway.

[jesilvas]

MAP sensor, EBP sensor, BARO even maybe. ICP.

[hollister25073]

What's baro? And can all these be cleaned in re installed?


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[jesilvas]

BARO sensor senses barometric pressure. I just googled 7.3 baro sensor and found it's only a real one E99. Maybe it isn't a big deal.
MAP can't be cleaned. It either has a cracked/loose boost tube going to it from the spider.
EBP can be cleaned. - Welcome to guzzle's Exhaust Backpressure Sensor Cleaning Maintenance Web Page
ICP - Usually it'd run bad if it actually was bad but it's worth a shot.

[hollister25073]

Yeah that's why I kinda ruled out icp cause it still runs like a champ just crappy fuel mileage but you never know


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[7.3550Duty]

try unplugging the ebpv and run it like that for a few tanks and see if it helps, then if it does, just leave unplugged lol

[INFRNL]

I would say EBPS/tube, get them cleaned, possibly IPR. If there is any oil in the icp, then it will need replacing; there should not be any oil in it.

if the truck still runs great its probably not the ebpv.

I say if it just started, then its a sensor of some sort. I replaced my IPR, ICP and cps, I am getting the best mileage ever now. Still nothing compared to others but good for me. 14ish city/ a little over 17 hwy. Most I got before was 12.5 no matter what. I recently switched to PHP chip/tunes, so thay may have helped too.