im getting 15 or less mpg. its been like this for a while, and im pretty sure it happened around the time i changed my o2 sensor i got a 97 duratec atx, and the o2 sensor i changes was the one closest to teh cat (not the precats)
TTT, I'm getting around 10 mpg!!!
anyone ???????
im a poor student who cant afford to buy this much gas !
Have you looked at that O2 sensor lately? Maybe the wires melted to the exhaust.
Only other things that cause really bad fuel consumption (if it still runs somewhat normal) are temperature sensors or a really whacked out MAF.
Smell your oil and change it if it smells like gas!!!
Check:
1) Spark Plugs (I change mine every 30-40K)
2) Plug Wires (Arcing plug wires kill mileage)
3) o2 Sensors (Common culprit, though an expensive one)
4) Dirty Air Element (Could be exacerbating the problem)
5) Cold Weather/"Winter Gas" (Lower mileage in general)
6) Clogged Fuel Filter (Doubt it, but a possibility)
7) Driving Habits (self-explanitory)
It could be a combination of any of these. If you've already done the o2 sensors, I'd hit the plugs and plug wires next along with the fuel filter.
Unless you're throwing a CEL, it's going to be hit or miss, so I'd start with the least expensive stuff first.
Best of luck!
Originally posted by JaTo:
Check:
1) Spark Plugs (I change mine every 30-40K)
2) Plug Wires (Arcing plug wires kill mileage)
3) o2 Sensors (Common culprit, though an expensive one)
4) Dirty Air Element (Could be exacerbating the problem)
5) Cold Weather/"Winter Gas" (Lower mileage in general)
6) Clogged Fuel Filter (Doubt it, but a possibility)
7) Driving Habits (self-explanitory)
It could be a combination of any of these. If you've already done the o2 sensors, I'd hit the plugs and plug wires next along with the fuel filter.
Unless you're throwing a CEL, it's going to be hit or miss, so I'd start with the least expensive stuff first.
Best of luck!
new wires and plugs (motorcraft) less than 10K ago
KKM installed less than 2 weeks ago (i reset computer)
ive switched between 87 and 93 octane gas, same for both
fuel filter changed less than 10K ago (napa silver)
ive tried babying the car, still got horrible milage
Swap out the other o2 sensor or check you cat (maybe getting plugged). Might try to get a local mechanic to check the cat for you. I think you can get pretty nasty mileage when a cat's getting plugged up...
I'm running out of ideas here. Anyone else care to step in?
Hey Poop, it's been a month now. 
Quit Playing Around
Have you checked anything? Have you checked the codes again?
Even if the CEL didn't come on there might be a code showing it didn't reach closed loop operation.
Originally posted by Rogerm60:
Hey Poop, it's been a month now.
Quit Playing Around
Have you checked anything? Have you checked the codes again?
Even if the CEL didn't come on there might be a code showing it didn't reach closed loop operation.
there are no codes. ill try to find some time to get down to autozone (its like 20 min away)
Isn't there a recall for the cat? I remember something about it corroding and it should be under recall.
really? it downst have any warrenty left taht i know of
i just called the stealership about the cat, they said "if its not teh cat you will pay the diagnostic fee" i was like "how much is it?" and they said "probably $120"
i replied "for that price i can buy a new, hi-flow one... click"
so...
is there any free or inexpensive way of checking the cat?
The sensors downstream of precats or upstream of main cat control nothing
The sensors upstream of precats control fuel and air
There are ways to check everything.
For the cat you need a pressure guage. I use an old vacuum/fuel pump guage. just stick it on the lower EGR pipe nipple where the DPFE attaches. REV it some and watch the guage. Normally it might peak at 3psi but mostly stay around 1psi and below.
You said this started when you changed the O2 sensor so that needs to be checked. First look at the wiring for damage on the front sensor under the exhaust manifold. Get an analog voltmeter, a cheap one will do. Use alligator clips and pins, or piercing clips to read the voltage at the plug or by piercing the wire insulation. Two wires should have yellow stripes, these are for the heating element an should have 12v across them. if not check fuse 13. The other two wires are ground (black or brown), and the sensor output (white or grey). With the car running you should have .45v on the meter and the needle should wiggle back and forth very rapidly. If there is no voltage or it is below .45 volts the car will run rich like yours.
Get out there and try it, it's realy not that hard. just don't short anything out or burn yourself. Later you can use the meter to test the coolant sensor and see how the MAF works.
If you won't do this, I suggest you put the car on diagnostic equipment and get a printout. This will tell you how well all of the sensors are doing and pinpoint the problem.
And check for gas in the oil!!!
The engine will die if too much gas gets in the oil!!!
how much will a cheap voltmeter cost? also, is there an easy way i can get under my car?
thx for the help guys
I've seen cheap voltmeters as low as $12-$18. Try Wal-Mart or Radio Shack. Put it up on blocks, my old ramps are usless now because all the new cars are too low. Oh well, maybe I'll get a pickup.
ok, its cold as hell out, wet too, i dont have a garage, and all i got is some old ass ramps. that thing to connect your laptop to your car, would that be useful? i heard it reads exactly how the engine is running. if thats the case and this would help me out, ill order one today (someone give me the link please)
thx, russell
anyone know if that thing to connect my laptop would help me diagnose the problem??
Most do.
Look at the picture here:
Proscan
Here is a suggested source for a OBDII Interface to a serial pc port. (Your laptop might not have a serial port.) My very old one does: obddiagnostics.com
I bought one and have checked it out with both DOS and Windows software.
checking in late here so suggestions i offer have prolly already been made...i too was getting pretty crappy gas mileage...in the teen's consistently city and not alot better highway...
i changed plugs and wires to whats in my sig...cleaned the throttle body and the egr ports (which got rid of cel i had for 6mos)...added monster flow filter and regularly add REGANE by gumout to the fuel tank...all of these things make for a noticeable improvement in performance and a bit of improvement in mileage...im more concerned with performance so this is acceptable for me
i've gotten older and wiser (i hope) and so now i change my oil regularly and make sure to use only some of the better oils on the market...usually mobil 1 in the engine and the atx
those things have improved overall driveability and performance but the coup de gras was installing 'quality' tires on the front about a month ago...kum-n-ho's ecsta 711 205/50hr-15....the tires made the most appreciable difference in mileage
now my city mileage is better but still sucks cuz there's lots of wide open straights and other fun places to drive hard....on the freeway however my last 3 trips to see mom 100+ miles one way have yielded me ~31-37mpg and i dont baby my car