need help i get 100km with 25 liters of gas

[summitawd]

i get 100km with 25liters of gas
can some people here tell me a few thing i like what part 2 change so i can save $$$$$$ some peop;e told me i should get 100km with 14 to 15 liters
i didnt do tune up yet but ill reather do all my repairs at one time so i have less down time it a work van
i get the same mpg as it load or not and i got new wheels
and when i floor it doesnt go it revs but goes really slow but when i give it half on the pedle it moves out good so new trany or rebuild
so tell me every thing u know
and the only mods i have done it lift the back end with larger leaf spring and 2 battery 2 power the stero and ac to dc converter
also any one here has put the front of there van on bags need some info and so i can have it level right now it like the old school car with the back end in the air and the front on the road

[astro355]

Doing all of the repairs at the same time will make it hard to diagnose what the actual problem is. If you know it needs a tune-up, do that first and go from there.

[ihatemybike]

I used this tool to convert to MPG/US.
http://www.onlineconversion.com/fuel_consumption.htm

That is 9.4 MPG to us here in the states and not good at all. My 90 day average with Grumpy is almost double that.


A good tuneup might help and is never a bad idea, but your comment about flooring it vs half pedal does make it sound like you are losing power somewhere in the trans. Does the high rev / no go only happen from a stand still or does it happen when you floor it at speed too? When was the last time the trans had its fluids/filter done?

What conditions do you mostly drive in? Hills, traffic, hi-way, etc.

Please take the time to add your van's information to your profile/signature as this will help us in our diagnosis.

[astro355]

ihatemybike,

a lot of times transmissions shift funny because of a problem starting with the engine. So if the engine is not putting out enough (expected) power, the transmission will act goofy also.

It makes it a lot easier to diagnose a problem when known faults are corrected.

[rev_les]

a lot of times transmissions shift funny because of a problem starting with the engine. So if the engine is not putting out enough (expected) power, the transmission will act goofy also

most people don't realize, a poorly tuned engine, esp on the older vacuum modulated setups, can kill an automatic transmission.

[summitawd]

hey there thanks 4 the info so far
ill give u some more imput
i drive a mix city and highwaydriveing
it a 97 safari cargo but it fully load as i mean it got pw pl abs tow kit lsd rear end trans cooler larger leaf spring in the back and it purple to and it all from gmc too
i talk to the last guy that own it and he told me when he got it he maxed it out because it was a tax wright off 4 him
and yes it lsd in the back i know because when i do a brun out both wheel leve a mark
and so far as my trans proble i have think i found the proble it might be the cat so im going 2 put a test pipe in there and the other reasonis that on the highway i can drive 100 km or 65 miles and flooor it and ill will be doing 180km or 110 miles in a few sec and i dont what 2 go faster because the van starts shaking