Well i bought this 88' TBI and it just sucks down gas what can i do to make it preform like new and get great gas milege, my neighbor down the street got like 18 in city and 28 on highway, what things can i do to restore it to orignal glory, (of getting good MPG and running smooth?)

 

Start with a full tune up: Distributor cap, wires, plugs, check the timing. Change the PVC valve, fuel filter, throw on a clean air filter and then see what that nets you. After that, you can start spending money. Full 3" exhaust, transmission service, etc.

The best I ever did in my car was 25MPG on a trip to LA from the Bay averaging 80-85MPH. That's a little over 2500 RPM with the tall gears in the 2.73 peg leg rear end gears on the stock Firebird.

This topic gets thrashed about all the time here.

Just do a

 

First thing to do is to take a highway trip and see what it actually gets. That 305 is a mileage champ usually. Then go from there.

 

Be gently with the pedal on the right.

 

The previous owner tried messing with the odometer cause a trip around the block a couple days ago ended up totaling 34 miles? Is there any way to fix that? Also my gas guage might be a little funky cause i noticed it goes up and down?

 

the gas guages on all these ares are a little funky after age. That something your just gonna have to live with.

As for MPG, full tune up, replace the o2 sensor, tires inflated properly, have alighnment checked. If you dont have alot of electronics in the car, maybe a crank pully. But most of all, install a vac meter in the car and not rudely saying "learn how to drive it". Ive increased the mpg in my grand prix by 2mpg in town, and up to as much as 5mpg on the interstate by learning its "sweet spot".

 

no the gas gauge is not FUNKY it goes up and down for a reason. in your gas tank on the same assembly the fuel pump is on there is a fuel float. this float reads the level of gas and when you stop or accelerate the gas moves around in the tank making it go up and down hence the gauge dont worry about it most gm cars have it they recently fixed that problem in the year 00 i think around at least because my 98 moves a tad. it depends on the design of the inside of the tank.

 

Hey Dale, how do you know where the "sweet spot" is on the vacuum gauge?

 

The highest speed with the most vacuum is typically the sweet spot. Keep the vacuum high, the fuel delivery will be the least, and you will get good mileage.

 

Every car is different on the sweet spot. You cant just install it and "bam" you have better mpg. You have to watch it, drive, calculate, remember where that guage was. But generally yes, fastest you can go with the lowest suction on the engine. You will be very surprised how sensative the engine vac is.

I have yet to figure out in town if taking off ***** to the wall up to the speedlimit, or granny take off is best.


My GTP, it does best on the interstate between 66-70mpg and pulling 12lbs of vac or less (14,16,18, etc). If I go past 10lbs of vac, it starts quickly dropping.

I have yet to install one on my camaros, but I will.

 

I very much agree with this statement. I take off moderately in-town to keep the rpms up and the engine in its powerband. I get to speed much quicker and it seems to net better fuel mileage than creeping up to speed at lower rpms and higher engine loading.

On the highway, my best fuel mileage is at approximately 2,000 rpm and 14 in/hg of vacuum. That is approximately 75-80 mph with my 3.07 gears and 29" tall tires. At 75 MPH with the cruise control set and the A/C on, I can get between 18 and 19 mpg consistantly.

 

An open or to low of a temp thermostat is the number one reason for crappy mpg.

 

If you are talking about an engine never reaching operating temperature and remaining in open loop, I guess that would explain it.

 

I still have the TBI setup on my car. totally stock it got around 14 mpg around town and about 16 highway. my instructor in school told me that if i advance the timing abut 6* and use 93 i should get better mpg...well he was right...went from 14 up to 16 city, and 16 to 18 hwy. then no other changes except open element K&N, headers, no cat, and 3 inch back flowmasters got me to 18 city weather i'm hard on it or not, and around 22-24 hwy at about 80 mph. gave me a nice power boost too.

 

onebad89RS,

Didn't your miles per dollars (MP$) go down?
in the city you got a 14% increase.
and to answer my own question....

Based on the national average gas price.
Premium is 10% more than regular.

 

Well where i'm at the diffrence between 87 and 93 is only about 20-25 cents. and usually i fill my tank. so thats only 3 bucks extra i spend for 93. which really is nothing to worry about. i'm not concerned with gas mileage till it goes over 3 bucks/gal again. but the whole thing evens out by getting more miles from a tank and simply spending $3 more for a full tank.

 

dont forget your fuel filter and pump, if they're the stock ones, time to change them out
youll notice a boost in mpg

 

In the last 6 - 12 months I have changed my fuel pump, fuel filter, had my fuel injectors cleaned, rebuilt my throttle body, had the throttle shaft rebushed, performed some of the ultimate throttle body mods, changed to an open element air cleaner, added an injector spacer, changed my spark plugs, wires, cap, rotor and coil. I checked my MPG last weekend after driving about 200 miles, about 80% highway. I'm getting about 25.3mpg and that was cruising on the highway at about 70 mph. I think if I was doing just straight highway driving I could probably get close to 30 mpg.

 

Learn to tune...

There are alot of guys running stock motors getting PHENOMINAL milage street and highway.