Horrible Fuel Mileage

[TheDarkAngel]

I know I do a lot of town driving and that's horrible for mileage, but I get 15 MPG driving with a very light pedal. Last tank included about 100 miles of highway as well, and still came out at about 14.6. I'm thinking about changing the spark plugs, wires, and possibly a fuel filter. Anyone have any helpful opinions? The engine has 156k on it, N/A 3.8.

 

[Fivefingerdeathpunch]

Clean the MAF.
New iriduim plugs and new wires.
New air filter.
Clean the Throttle body too.
Run some injector cleaner.


Might help get some back, but these cars tend to eat gas in the city. I drive 95% city, and even in the summer I only get 16ish.

 

[TheDarkAngel]

Ok, that's mostly what I was expecting to hear. Still tho, 14.6 is horrible for a V6.

 

[stealthee]

Driving around town kills mileage. If I only drive back and forth to work I get 23 mpg. If I do any running in town It drops to 19 mpg and that is with most of my driving being on the highway/bypass. You might see some improvement, but don't expect it to be major.

Also, are you actually calculating mileage, or basing it just off of the DIC?

 

[ericspecullaas]

DIC lies to ya. its best check at fill up with your own math.

 

[stealthee]

DIC lies to ya. its best check at fill up with your own math.

Yeah that is why I asked him. Mine is never right. On one trip DIC showed 25.3 mpg and when I did the math I got 28.5. Weekly flll-ups are off by anywhere from .5 to 1 mpg.

 

[ericspecullaas]

Question stealthee. do you have to have the last word on everything lol kidding

 

[stealthee]

No, I'm just bored.

LOL

 

[ericspecullaas]

then get some more beer.

 

[Madness]

New Iowa gas blends?, heard it is not so good

 

[LeadfootCJ7]

What mileage do you normally get?

 

[loopy smurf]

Check your tire pressure too...

 

[REDCRAPGP]

Tune up time

 

[fromne]

Kind of a long shot but if you dont have success with anything else, make sure your cats aren't clogged. This happened to me and it took a month or so of crap mpgs and 16 seconds to 60 (I got bored and timed it) before I took it in and found out I needed a new cat. And I only had 90k on it then

 

[disallow]

I'm having the same issue with my 2000 GT. Crap-ass fuel economy. got 21MPG today on the way in, all highway. I have the trip computer, and find that the 'gallons used' value is actually bang on correct, usually within .25 gallons based on filling up and comparing to the value on the computer.

This car should be able to get 25-28 on the highway.

Planning to do plugs and wires. But I really doubt this will do anything. Ran seafoam through it when I got it, and there was no carbon buildup to speak of.

Only other issue is my thermostat. It seems to run a little cool, so I am thinking the thermostat is stuck open ,and casueing the engine to run too cool. In winter it would obvioulsy be worse.