this is insane!!
my jimmy has always had crap gas mileage since i got it 5 yrs ago, my friend borrowed it once to deliver wine and filled the tank back and said he would rather fill the back seat of his acura and his trunk because the gas was more than double lol.
taller tires will give better highway mpg but less in the city generally but tire tread plays a factor as well, im on snow tires, but not too aggressive to the point of loosing a large amount of gas mileage.
ive run fuel system cleaners, use syn oil, and all that maintenance crap but nothing helps.

what are these cheap and free mods? got any links??
i know a few for my caddy like my stock airbox hack to a CAI with cone filter and tb bypass.

 

The biggest boost to mileage that I ever realized was from cleaning my MAF sensor. It was pretty dramatic, but it had around 185K kms on it and it had never been looked at before. In fact the PCM threw a MAF sensor out of range code that got my attention. I was in about the same sort of mileage range as you I suppose come to think of it. It ran like crap but I never really noticed how bad it had gotten until I cleaned the sensor with some methyl hydrate (denatured alchohol) and a toothbrush.

I also recently descreened my MAF and deshrouded my throttle butterfly, but I won't get into that here! LOL (It did get me another 5% on the last tank and a whole lot better throttle response, but the mileage could've been due to just about anything really.)

 

ya i actually saw your thread on your build, including the maf.
ive heard both sides to the maf mod over the years, some say its amazing, some say its nothing.
i dont want to damage mine so ill take a look at it but i dont think ill be pullin the screen out..ill go clean it now actually.
last 2 rims are getting mounted in a couple hrs, cant wait to see how this thing drives with a wider stance, its wobbily as hell!!

 

Depends on the driving you're doing... all in town and stop and go I'd get about 330 to 400 a tank... strictly highway driving I'd get over 570.

Get your hands on a CAI, a catback (replacing muffler or getting a true cat-back... don't get muffler shop "kinked" piping, you're not gaining anything except noise.) and a PCM tune... you'll pick up NOTICEABLE gains and fuel mileage at the same time.

 

all the wheels are on and to be honest, it drives much better, i cant believe GM made this thing with such a skinny wheel base to begin with. i dont think im going to even need to replace the shocks now but we will see how it goes over the next week or so.

as for the gas mileage, i just got 314km to 56 L of gas, i dont know what that works out to but its horrible. (just filled up to the top)
didnt get around to doing anything else to it today...maybe tomorrow.

 

I like, I like.

 

Yeah, I have no idea why they put such skinny tires on the blazer series mine drove much better when I got my new tires. I still don't get the 17-24 mpg mine was estimated at either.
btw, is that a diamond white Cadillac cts in your signature?

 

ya the estimated mpg is bull...

yup thats my CTS, she only comes out in the summer, just gettin ready to put her back in storage...hate this time of year!
some of the pics of the truck you can actually see the CTS next to it. its got a couple mods on it, the headlight eyelids i actually designed and a couple guys on the CTS forum have asked me for them but they have to be made while on the car so i didnt, but i did made a set for one of my friends.

 

Nice CTS, and I think rear spacers are in order for the Jimmy? lol.

Did you ever consider lids for the tails on the CTS? Might look neat.

 

the back wheels stick out a little and i was going to get spacers and not the 2wd rims but i really dont like spacers unless they are hubcentric because they dont always line up right. also i just dont know who to trust with a quality product, i would want to find a tool and dye shop to custom make them then hammer in oem GM wheel studs or from a reputable parts store. i just dont like cheap parts that can affect vehicle safety.

lids on the caddy tails? do you mean tinted covers? lots of guys use night shades or have bodyshops mix clear and black to make a translucent tint paint...to be honest night shades is good for small things but large you see flaws and i had a big issue trying to tint a spare light with the black cracking.
also i like my caddy tails red, and the 3dr brake light is stupid expensive to replace if it was damaged ($900 not kidding...mine burnt out and i rebuilt it with leds and my walk through has saved a lot of cts guys a lot of money and only cost $20)
lol anyway this isnt my CTS build thread, and i dont know if that would be allowed in here lol.

i saw a few theads on led swap for the dash cluster on the jimmys... is it really just pull the cluster our and the bulb twists out? i have tonnes of leds kicking around, i actually switched all the map lights for led a couple weeks ago.