MPG is dropping

[DSM_IKE]

Ok, so i havent really done anything to the car, but i seem to be dropping the mpgs like crazy. Ive dropped from getting 150 miles for 6.8 gallons of gas to 113 miles to 6.8 gallons. Why would i be dropping so many mpgs.

 

[my dreamt dsm]

There's many reasons.
Bad tires.
Boost leaks
Driving style.
Spark plugs

I notice my mileage drop when I added fuel injector cleaner. But after a while the mpg came back. I also learned to stay off boost more. Also when I added an intake I notice an amount of bad mpg. For some weird reason the 1gen bov cost me more mpg then the greddy type s so right now I'm on the type s. WEIRD!

 

[DSM_IKE]

well i my tires are the same ones as when i got the car, they still have plenty of tread, Fixed all boost leaks as of a week ago, Driving style is the same as when i first got the car, and spark plugs are only a little over a month old. I am running a greddy type s bov as well. There is no cel on the dash.

 

[my dreamt dsm]

You know one of the funny thing is it went away by itself besides the bov. The only OTHER thing I notice was during that bad mpg thingy I was having over heating problems? Once again... WEIRD!

 

[DSM1G90]

Welcome to UTAH and the Intermountain West where it really gets COLD in the winter, esp down there in PG by Provo. Plus, you're in a great storm track at the moment and that can have an effect as well ...

Cars usually drop in MPG during the wintertime - kind of a given fact that's been known for generations.

During the summer, my Laser averages 26mpg, but during the winter months I'm barely above 20mpg ..

I don't get all excited about it ... - DSM

 

[Absit]

Winter gas, yo.

 

[DSM_IKE]

Guess I didn't figure that crap they like to throw in the gas during winter. Damn Jews anyway.

 

[DSM1G90]

... ! ... no such thing as "Winter gas" ... Gas is gas 24/7/365 all the time.

 

[GRAVEDIGGER]

... ! ... no such thing as "Winter gas" ... Gas is gas 24/7/365 all the time.

Your wrong.

There is a difference between winter and summer gasoline and it's in the RVP or Reid Vapor Pressure. The RVP is a measure of the volatility or how fast it will evaporate as temperature rises. A summer blend of gasoline will have a lower RVP than a winter blend and will be less likely to evaporate than the winter blend. This is higher in winter gas to help aid in cold starting. A summer fuel may actually have a hard time starting in the winter because of it's low RVP.

To the OP... Yes this winter gas could be why you're seeing less MPG. According to the EPA summer gas contains 1.7% more energy than winter blend gas which may contribute to your slightly better gas mileage in the summer.

 

[1 FAST TSI]

... ! ... no such thing as "Winter gas" ... Gas is gas 24/7/365 all the time.

not true...in maryland and in kentucky they add more corn juice to it about 9% 10% in winter months...then summer months..witch is about 4% 5% this the shell v-power iam talking about..its the best fuel i can get in kentucky..

Your wrong.

There is a difference between winter and summer gasoline and it's in the RVP or Reid Vapor Pressure. The RVP is a measure of the volatility or how fast it will evaporate as temperature rises. A summer blend of gasoline will have a lower RVP than a winter blend and will be less likely to evaporate than the winter blend. This is higher in winter gas to help aid in cold starting. A summer fuel may actually have a hard time starting in the winter because of it's low RVP.

hahaha i just read about that also like two nights ago..

 

[DSM1G90]

Gee...nothing was ever mentioned on this at any fuel station or any fuel company to my knowledge of the two seasonal fuels for the simple reason I never worried about my mileage during the winter in all the years that I've been driving in climates that had definite change during the year.

Guess I was never anal in this area and just took it that mileage goes down when it gets cold and returns to normal during the summer and lived with it.


Yet, interesting facts to remember .... - DSM

 

[nocardick]

When's the last time you checked/replaced your o2 sensor?Could be it....Also,do you check your tire pressure often,because you will lose some pressure because of this cold weather and not realize it

 

[hhuricane]

Possible o2 sensor or coolant temp sensor. Both can severely affect fuel mileage.

 

[16g DSM]

Got it! Leadfoot! someone cant stay out of the boost !

 

[DSM_IKE]

I want to change my o2 sensor but when I pulled it it looked.fine. again I have no cel on the dash. Tire pressure I check once a week. And Just curious, but if my coolant temp sensor was bad, wouldn't the gauge not work right?

 

[1 FAST TSI]

Gee...nothing was ever mentioned on this at any fuel station or any fuel company to my knowledge of the two seasonal fuels for the simple reason I never worried about my mileage during the winter in all the years that I've been driving in climates that had definite change during the year.

Guess I was never anal in this area and just took it that mileage goes down when it gets cold and returns to normal during the summer and lived with it.


Yet, interesting facts to remember .... - DSM

good gas is key thing for dsm's...i try to not ever mix fuels eather..i stick to v-power cause its the only one around here out of 3 brands. that is very resistant to knock*. compaired to others...i learned this from several other there dsmers that are WAY faster then i....SO I PAY ATTENTION TO THEM when they speak about performance do&dont's about this wonderfull powerplant call a 4g63.

I want to change my o2 sensor but when I pulled it it looked.fine. again I have no cel on the dash. Tire pressure I check once a week. And Just curious, but if my coolant temp sensor was bad, wouldn't the gauge not work right?

no it will work fine...but it will be tough to start every morning...and run pig rich.

 

[DSM_IKE]

I never have any problems starting the car, I only use cheveron premium gas (Believe it or not, there really isnt to many shell stations around here) Im banking more on the fact that i forgot that they put more ethanol in the fuel during winter.

 

[1 FAST TSI]

I never have any problems starting the car, I only use cheveron premium gas (Believe it or not, there really isnt to many shell stations around here) Im banking more on the fact that i forgot that they put more ethanol in the fuel during winter.

good chance..mine makes more pwr in the winter.( colder air) but bad mpg...also i BLT. my tsi everyweek and i find a'lil leak everytime..it would not hurt to do one.. last week the little rubber gromet that seals the trottlebody flapper on the cable side..was leaking so bad it would not even hold 10psi charge for 4-6 seconds.. my mpg dropped like a rock..

what plugs are in the car? whats the gap? have you cleaned your air filter lately? have you check your ignition timming ? 5*BTDC (with grounded ECU) all these things matter. for best performance out of your car

 

[DSM_IKE]

Running ngk's Only a little over a month old, gap is set at .28. Cleaned the filter last week. Haven't done a timing check yet, and ill check the throttle body tomorrow.

 

[DSM1G90]

...amazing how timing can slip without knowing about it ... before my smog test, my timing did slip to almost TDC and when I redid the timing back to 5BTDC, I did get some lost mileage back and better power... and passed the sniff test.

-DSM

 

[1 FAST TSI]

...amazing how timing can slip without knowing about it ... before my smog test, my timing did slip to almost TDC and when I redid the timing back to 5BTDC, I did get some lost mileage back and better power... and passed the sniff test.

-DSM

thats the crazy thing about dsm's..if i advance my timing to say6-7 BTDC i got better mpg (OUT OF BOOST) and spooled faster...BUT it got a few hits of knock* and actually lost power after 4500 rpm. it seamed better for city stop and go style of traffic...but bottom line is its not good to do it so we should'nt.

Running ngk's Only a little over a month old, gap is set at .28. Cleaned the filter last week. Haven't done a timing check yet, and ill check the throttle body tomorrow.

good idea...tell me what color your plugs are also when you get to it....also i did some digging and found out i cant find them gommets for a 90.. found 91-94 but no 90's...the reason is i oun a 90 5 speed and a 91 auto...i kinda wish they were both the same years..but mebe thats agood thing..so one don't end up a parts whore