Lots of ?'s

[VetteOwner]

ok first off, My truck is over 12 years old (136,000 miles) and still has the origional O2 sensor...now the truck runs fine (havent had to replace anyhting) but im wondering if i should replace that sensor. cuz i cant seem to break 25 mpg... its a 2.2L (4banger) 5speed. ive tried everythign from driving slow upshifting early. (doesnt liek that too much) seems liek i get the best MPG when i shift at 2500 rpm. last fill up it dropped liek a rock from upshifting early and generaly keeping it in a higher gear at lower speeds (i saw 22mpg ) so im not gonna be doing that again.

What are these MPG meter/calculators you guys keep mentioning? i read the top thigns to do to improve MPG and that was one of the lower ones but still.

Now my chevette is a nightmare... since its fully carbed the outside temps like to screw with my MPG and i cant get the airfuel/idle speed set right...
i had it set to where i could get 25-26mpg in the winter but now that its warming up its starting to kill my mpg with the current carb settings...i just changed it today so we will see what happens...

thats why im kinda leaning towards my truck to do what i can to improve it the most...
BUT it curently has like a strange studder when im kinda lightly on the gas when the rpms are about 1500 (idles at 900) its usually in 2nd gear. then it does it when im at 30mph. its right between 2 shift points so 3rd gear is too low for it so it seems like the truck is floored when its not, but 4th is kinda too high cuz if i come to any type of hill it starts doing this bucking hesitate thing again.

it kinda studders and very lightly feels liek the truck is bucking...almost like a weak spark or something. i dont remember it ever doing this so its got me a tad worried. I replaced the plugs and wires when i bought it 20K miles ago. recently when it would be wet out it would missfire kinda bad. 1 or 2 cilynders at least. (did this once before cuz the coils kept getting wet) so i took them off an put some more dielectric around the contacts and in the plug boots to see if that helps...

[DracoFelis]

Originally Posted by VetteOwner

What are these MPG meter/calculators you guys keep mentioning? i read the top thigns to do to improve MPG and that was one of the lower ones but still.

The most common/popular one is this (and runs about $170, if memory serves correctly). It apparently works very well (giving you accurate real-time data, including fuel usage data, that is normally hidden), and is supposedly very simple to install.
http://www.scangauge.com/

The only "gotcha" (which is why I'm not using one btw), is that it only works on cars/trucks new enough (mostly 1996+ vehicles, buy check their full vehicle compatibility list to make sure) to have the vehicle's ECU (engine computer) support the new style data port. So if (like me) your vehicle is old enough to not support the proper ECU data port, the only way you will use that device is by first upgrading your car's computer (a task that is generally more trouble than it's worth).

There is a second style device (called a "Super-mid"), apparently made by another forum member on this board. That device supposedly gives less info than the ScanGauge, but it can also supposedly can be made to work on some "fuel injected" vehicles that are still too old to run the ScanGauge. At one point I looked into getting the SuperMid for my CRX, but the hassle of installing it into my car (the SuperMid will work on some cars that can't take a ScanGauge, but it isn't as easy to install), has so-far kept me on the sidelines.

[cfg83]

VetteOwner -

The ScanGauge may work for you because the OBDI(?) implementation was put in place by different manufacturers at different times. Your truck may not have all the data points available, but it might be enough for you.

Also, I think a "Vacuum Gauge" is a tried and true way to infer good MPG driving style. I think that would be a good option for your Chevette.

This post :
http://www.gassavers.org/showpost.ph...62&postcount=4
Leads to this :
http://www.centuryperformance.com/vacuum.asp

This post :
http://www.gassavers.org/showpost.ph...70&postcount=6
Leads to this JC Whitney model :
http://www.jcwhitney.com/autoparts/P...gallon%20gauge

And here's a picture of one installed :
http://www.gassavers.org/showpost.ph...82&postcount=9

CarloSW2

[Hockey4mnhs]

i wish i could get a scangauge but my car is to old

[Peakster]

I love my Scanguage so much that I don't think I'll ever buy a pre-1996 vehicle again (unless it was super unique... like a Cimarron ).

[VetteOwner]

hmm looks like guages for both it is. My trucks only OBD1...do they make them any smaller?