Let's see here, all the cars I've owned in the past, I've strived to squeeze more mileage out of them. Can match or slightly beat EPA ratings in darn near anything. Drove my boss's Expedition (rated 14/18) while towing a 6500lb trailer and averaged 19.2mpg over 1100 miles. It's fun.
But then our ever-growing family decided to rear its cute little head and require us to purchase something with 8 or 9 seatbelts. We searched for over a month and couldn't find anything we could buy for cash. Then a $900 1984 Suburban showed up online and seemed to be in good shape. About the time we thought we'd keep looking for a minivan or a station wagon, my Celebrity died. We thought, let's look harder. Then my wife's Lumina started acting up and we thought, forget it, let's get the Suburban.
So here we are, and I'm keeping track of my gas mileage in this monster. First tank was an even 10mpg. I thought, this is going to be BAD. Second tank 9.45mpg. Third tank 9.75mpg, fourth 9.54mpg. So I kept driving gentler and gentler in an effort to make it better. Fifth tank 8.3mpg. This is SICK!!!
So I changed the oil and filter, the air filter, rerouted some of the vacuum lines, replaced the PCV valve, its grommet, the breather filter, its housing, hose, elbow, and grommet, and tried again. 9mpg even.
I gave up on trying to get better mileage and drove it like I stole it for the next week. That 40 gallon fill-up lasted longer than the others. 11.6mpg!!!
So I'm going to tune the engine, set the idle/mixture screws, lower the idle speed, set the timing, hook up the vacum advance, see if there's a lockup converter that should be engaging (it's a 3/4 ton 8600lb GVWR truck, I don't think it has lockup), and air up the tires to max (44/51 seems high but max on these load range E tires is 80psi all around...I'll have to go to a truck stop to find a compressor that'll do it).
Wish me luck, if I can't crack 15mpg in this thing by summertime, I'm giving up and finding a diesel 'Burb to replace it.
you need a miracle or a different car I sagest you go find two little crappy beaters. Example, a tercel you can find them cheap just by one with a salvage title. If the work was done at a dealership you know what your getting and it will serve its purpose.
84' Burban huh? You should try replacing your oxygen sensor and or catalytic converter. Hmm seems like a good project that with some well deserved maintenace will hopefully prove to be a good investment. Oh ya and like the title says, convert to TBI. Best of luck to ya