anyone have any luck with this at all? I have an 2004 zx5 2.3L model and the exact same thing has happened to me this past year. And it was happening over the summer too so i don't think weather is affecting it much. i don't know a whole lot about cars so if anyone made any progress with this please let me know. Thanks.

 

Actually i agree that is not dumb. If the thermostat is stuck open the engine runs to cold making the fuel dump faster to keep the car running. That will be one reason for poor gas mileage.

 

I just wanted to see if any of you guys with this bad gas milage problem ever figured anything out with it????One suggestion I had for the guy that originally started this thread he said the gas milage actually went down 4 miles to the gallon after replaceing plugs and filter I was just wondering is there anyway you guys may have changed your own plugs and didnt double check the gap before installing them. I know alot of the plugs people buy today are pre gapped supposedly but Id never trust them right out the box,, not unless you want 4 at .040 and 2 at .065 I have personally had them this far off new fresh out the box and they were supposed to be pre gapped ready to install...just a suggestion i figured id throw out there. Also with the thermostat theory are you guys saying with newer cars it makes a difference rather the thermostat is stuck open or somthing? I just wanted to point out that I have had numerous old and new cars and trucks that i have just taking the thermostats out all together and it made no difference on gas milage,,The biggest thing i think ever happend with a thermostat out of the car all together was i forgot to reinstall before it got really cold one year and it took forever to get some heat going but other then that engine ran fine and gas milage never was effected. On my V-8 engines and truck engines im sure i would have noticed almost a 50% reduction in fuel economy when i took the thermostats out.

 

I have had the same problem on my 02 focus, with exactly 45k miles on it!!! I do notice that my throttle position sensor is failing, because when i put it in neutral(its auto) the and revv it, the rpms wont drop under 3000rpms, unless its put into gear(not a good idea) or if you let it take its time, which can be from 30 seconds to 2 minutes... its ANNOYING and the dealer says theres nothing wrong... IDK... but i get an average of 17-22 mpg depending on how heavy my foot is!

 

This has me confused but all I know is Id be pissed if I were focus owner!! I have seen guys conplaining on the explorer forums about only getting about 15 miles to the gallon, but those are 4.0L engines in 4 wheel drive suv,weighing probably twice the weight of your cars. well I hope someone figures this out,,, sounds like alot of you guys would benefit from it....