Gas Mileage

[Jimmy F]

Morning all:



Question, I have been getting increasingly worse gas mileage.. of course as the gas prices have been going up...



Last night I put just over 16 gallons in.. and the trip had 156 miles on it :wacko:



Anyone have any ideas what might be wrong, or has anyone else experienced a similar situation?



Any info is helpful.



Jimmy

 

[Fred]

Winter blends of gasoline contribute to lower than normal gas mileage.

 

[Kevin Palmer]

I will repeat what Fred has said. The winter fuel will lower your mileage a substantial amount. So on top of all the other reason winter lowers your mileage the fuel itself does as well. In general you will have lower mileage in the winter time even if there was not a winter fuel blend.



Has to do with the engine taking longer to heat up, driving on snow, ice, slush etc. Unlike summer roads, in the winter time, your virtually running up hill as your always running over snow and what not...

 

[Eric H]

I took my wife's '02 ST to the dealer (I thought it would be covered under the ESP warranty) for the same problem. They said there is a TSB for this problem that calls for the PCM to be reprogrammed. Now our MPG is back up around 17 - 18 again.



They also ended up rebuilding the transmission this week, so hopefully the MPG will increase even more.

 

[Todd Z]

Unless you drive like old folk, the average ST around here seems to get under 20MPG...

Even taking off from a light a little faster seems to Kill MPG......

The winter gas has a lot to do with it...



Adding intakes and exhaust frees up some power and gives you more MPG...

I know I am 25MPG + on the highway...

Around town I get 14-16 because I cant keep the pedal off the front bumper ...LOL



How are your filters???

Todd Z

 

[Jimmy F]

Thanks..



Eric did the dealer give you a TSB # for that?



Thanks,



Jimmy

 

[Jimmy F]

I have a K&N drop in.. clean it on a regular basis.. but not too much..



Not really sure about the other stuff



Jimmy

 

[Andy G]

My gas mileage went to $|-||T when my catalytic converters went bad. They started to clog up. Dropped me down to about 12MPG. I typically get about 19MPG now.



Cats are covered to 80K. Only other symptom is a loss of power at high RPMs.



But as others have mentioned, driving style, winterblend fuel, longer warmups, good filter maintainence, and of course a few mods can really impact MPG.

 

[Eric H]

Sorry, I don't have the TSB #

 

[Ryan Y]

Andy,

how did you know that your catalytic converters were bad? Does it cause a Check Engine Light? I am wondering because for about 9-10 months now I can't seem to break away from 12 miles to the gallon around town. Summer, winter, it doesn't matter, I'm in south Mississippi. I have even replaced plugs and wires with motorcraft and taylors... Should I visit my dealer? I only have about 500 miles left on my 36,000 warranty.



thanks

 

[Fred]

Ryan Y,



One way to check for a restricted CAT is to remove the large vacuum line from the brake booster between the master cylinder and the firewall. Put a vacuum gauge on the large vacuum line and observe vacuum at idle. Rev the engine to ~2500 RPM and hold it there for 4 or 5 seconds. Observe the vacuum. If, when you first rev the engine, the vacuum drops but then returns to close to where it was at idle, the CAT is OK. If the vacuum drops, and stays dropped, the CAT is restricted. Hope this helps.

 

[Jake Levin]

Fred, where would one get a vacuum gauge and how much would it cost?

 

[Fred]

Sears has them and any auto parts store should have them.

 

[Jimmy F]

Wel, I called my dealer today after reading some posts.. inquried about my sh*t mileage.. they said to change the PCV valve and the fuel filter.. I meantioned the PCM TSB that Eric H had meantioned.. 879 bucks.. of course not under warn...



Should I change those out?



Thanks,



Jimmy

 

[Eric H]

$879 !!!!!!:angry:



All I was charged was one hour diagnostic labor to reprogram the PCM. My ESP warranty did not cover the cost as there was not any parts replaced. As I said before, this made all the difference on both the performance and got my MPG back to nearly what it was when new.



I'm still planning to also replace the PCV valve sometime in the near future. Usually a person can just check these to see if it's still good. But the valve is located in such a PITA location, that I'll just replace it while I have my hand stuck back in there.



My brother-in-law works in an independant shop. I'll talk to him this weekend to see if he's able to get the associated TSB #.

 

[Wayne Foy]

Dont forget that I can also get you better mileage with the Xcal2

 

[George Anderson]

Wayne;



I searched for a description of the xcal2 but came up empty.



Can u point to a page describing it and what it can do?



Thanks

 

[Jimmy F]

Thanks WFoy..



Wrong keys.. I meant $89 bucks.. fingers were ahead of my brain.



Can I just go into the dealer and say.. I think my CAT is bad,., or are they going to charge me to diag. it before hand??



Thanks,



Jimmy