Poor Mileage, all of a sudden, worse than normal!
#1
Poor Mileage, all of a sudden, worse than normal!
Hey all...I know it has all been heard before. Also posting this in Exped forum. Just some background here:
1999 Expedition XLT, 4x4 5.4. 3.73 rear axle, etc etc. I know, I'm already set up for failure here....however that said, I was pretty used to seeing 13.5-14 town, and 16.5-17 highway. Now, no matter where we go, we get 10.3. City/highway, doesn't matter....10.3.
I'm not getting codes, I'm not running rough. I am noticing heavier than normal black stuff accumulating at the tailpipe...of course because it is running rich.
My first instinct was to check the Coolant Temp Sensor....it is the only thing I can think of that besides stuck open or shorted, will not throw a code, but will make the engine run as if it were cold all the time. Then I discovered that I don't have a Coolant Temp Sensor...that seems to be Navigator only this year this engine.
Anyway, any other guesses, other than someone siphoning the tank, or a flat out fuel leak that I can check for? Again, running great...just sucking way more than normal fuel.
Thanks guys.
Sam
1999 Expedition XLT, 4x4 5.4. 3.73 rear axle, etc etc. I know, I'm already set up for failure here....however that said, I was pretty used to seeing 13.5-14 town, and 16.5-17 highway. Now, no matter where we go, we get 10.3. City/highway, doesn't matter....10.3.
I'm not getting codes, I'm not running rough. I am noticing heavier than normal black stuff accumulating at the tailpipe...of course because it is running rich.
My first instinct was to check the Coolant Temp Sensor....it is the only thing I can think of that besides stuck open or shorted, will not throw a code, but will make the engine run as if it were cold all the time. Then I discovered that I don't have a Coolant Temp Sensor...that seems to be Navigator only this year this engine.
Anyway, any other guesses, other than someone siphoning the tank, or a flat out fuel leak that I can check for? Again, running great...just sucking way more than normal fuel.
Thanks guys.
Sam
#4
Yeah, tried the MAF. Its been hosed with MAF cleaner. LOL. I have not looked at the Air Temp Sensor however...any ways to check it via volt meter, etc?
Also in regards to oil consumption. Now using about a quart every 1,000-1,200 miles or so. Checked the easiest thing, PCV...it is fine darn it. Have lots of pooled oil down in the gully below the intake.
Also in regards to oil consumption. Now using about a quart every 1,000-1,200 miles or so. Checked the easiest thing, PCV...it is fine darn it. Have lots of pooled oil down in the gully below the intake.
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I had a similiar problem with my 03 5.4, poor gas no codes and only 60K. Finally threw a code for cylndr and I replaced all the plugs. They didn't look that bad but it was enough, after I replaced all is good. Mileage is up and throttle response is much better. Depending on you mileage it may be time? Before replacing the plugs I changed air/fuel/pcv valve that didn't help much.
GL
Lou
GL
Lou
#10
I had a similiar problem with my 03 5.4, poor gas no codes and only 60K. Finally threw a code for cylndr and I replaced all the plugs. They didn't look that bad but it was enough, after I replaced all is good. Mileage is up and throttle response is much better. Depending on you mileage it may be time? Before replacing the plugs I changed air/fuel/pcv valve that didn't help much.
GL
Lou
GL
Lou