I'm not sure what's going on here. My truck is running fine; save two things.
A sudden drop in gas mileage. I just changed my fuel filter, air filter, keeping up with my oil and I'm using good gasoline. I was getting about 16MPG in town. Now I'm getting about 8.5. What in the world? I've noticed my truck is idling about 200 rpm higher than normal. I'm thinking this is linked?
I have NO idea what could be wrong. I need some help here.
Also note worthy; my driving habbits have not changed. My commute to work is not nearly as long as it used to be. It's about 3/4 of a mile from my house. Does this have something to do with it? Does engine temp affect gasoline usage??????
Could the flowmaster I just installed do this????????
IIRC, you have an efi truck. id run over to a chain parts store and ahve them scan your ecu. its free. see what codes its pullin.
and yes, when the engine is cold, it will run rich to warm up faster so that the chilly passengers can turn on the heat sooner. 3/4 of a mile is not enough time for the engine to reach operating temp, espcially if its still cold out for ya.
IIRC, you have an efi truck. id run over to a chain parts store and ahve them scan your ecu. its free. see what codes its pullin.
and yes, when the engine is cold, it will run rich to warm up faster so that the chilly passengers can turn on the heat sooner. 3/4 of a mile is not enough time for the engine to reach operating temp, espcially if its still cold out for ya.
ride a bike?
IIRC? What is this?
I'll look into getting a scan. I just don't like the threat of these guys making up problems. So could part of the problem be my very short commute to work?
Most guys at autoparts stores don't get paid commission (just by the hour), so they really could care less about making up stuff to sell more products.
As for a short commute, an engine normally gets about half of its gas mileage until it warms up, so if you don't go very far, 8.5 sounds about right. If you want to be sure, go on some longer trips and check your mileage to really tell if you have a problem.
__________________
1981 Ford Bronco 300 1bbl. 4 speed Manual w/OD. K&N air filter, EFI manifolds, 2.5" exhaust.
3.00 rear end and 2000 RPMs @ 80mph!
Most guys at autoparts stores don't get paid commission (just by the hour), so they really could care less about making up stuff to sell more products.
As for a short commute, an engine normally gets about half of its gas mileage until it warms up, so if you don't go very far, 8.5 sounds about right. If you want to be sure, go on some longer trips and check your mileage to really tell if you have a problem.
Thank you, that is most likely it then. I was hoping maybe that was all. Because other than work, I really don't drive anywhere else much. My longest trip is going to church, which is about 10 miles at around 55 MPH.
For about 2 years I lived less than a mile from work and I never got mileage that bad. Yes, it will run rich at start up, but not rich enough to cause single digit mileage. I think it's fairly unlikely that your short drive is solely responsible for your mileage.
__________________
1990 F-150XLT Lariat Stillon the original engine with no squeaks or rattles at over 300k miles
4.9/M5OD/3.08
16.89@77.09
145 rwhp, 272 rwtq
2001 Lightning #127
13.18@104, no chip, no pulley, no nitrous
Confuscious say "Man who have no use for jackstand have promising career as jackstand".
For about 2 years I lived less than a mile from work and I never got mileage that bad. Yes, it will run rich at start up, but not rich enough to cause single digit mileage. I think it's fairly unlikely that your short drive is solely responsible for your mileage.
Yeah. After thinking about it I kind of agree. Before I had this job I had another that was close - not as close, but still close. I got 15 - 16 mpg then. I'll look into the codes thing. Kind of scared of what I might find. No idea what else could be causging 8.5 mpg?
Quote:
Originally Posted by fmc400
Bill, AB already told you this but I also believe it's due to your shorter commute. I agree with the rest.
I have a commute of .8 mi each way and after about 8 months of it I had sucessfully plugged up the cat. this resulted in an idle about 400rpms higher than normal a drop in mileage from 19-20 to about 9. I got rid of the cats and we are back at a solid 18mpg, no codes but it also had some off idle hesitation problems.
-Johnboy
I have a commute of .8 mi each way and after about 8 months of it I had sucessfully plugged up the cat. this resulted in an idle about 400rpms higher than normal a drop in mileage from 19-20 to about 9. I got rid of the cats and we are back at a solid 18mpg, no codes but it also had some off idle hesitation problems.
-Johnboy
Sounds like it.
So if I pull codes, will they tell me exactly what the problem is? For example, if it's a plugged cat, will I know? I thought I would lose power with a plugged cat, though. My truck seems to be driving the same.
How does it run? If the cat is plugged up enough to hurt your mileage it will definitely cause a noticable loss of power.
__________________
1990 F-150XLT Lariat Stillon the original engine with no squeaks or rattles at over 300k miles
4.9/M5OD/3.08
16.89@77.09
145 rwhp, 272 rwtq
2001 Lightning #127
13.18@104, no chip, no pulley, no nitrous
Confuscious say "Man who have no use for jackstand have promising career as jackstand".
That's the thing, SS. It's running fine just like normal. Starts good, accelerates good, idles good. The only things I've noticed is the obvious loss of mileage and a 200 rpm higher than normal idle - and the higher idle doesn't happen all the time.
I guess I'll just have to bring my truck into a shop to pull some codes. 8.5 mpg just isn't going to cut it.
Join Our Site - Its free, quick and easy!
