i have a 1990 formula and i know it being a V8 that it will suck gas like no other and i was wondering what your guys's MPG is. mine is probably 11 maybe 12 MPG. is that normal? maybe im just having trouble getting used to it because i used to drive a tacoma and it was a 4 banger and i would fill up $20 and it would last me 2 weeks. now i fill up $20 and it lasts me less than a week. so i just wanted to know what kind of gas milage you other guys are getting.

 

Most guys with an L98 350 like yours get somewhere between 20-24 mpg highway, like 16 mpg at best in town. 12 mpg is pretty bad, unless it's all in-town with a lot of flooring it. Might want to do a tune up.

 

ya most of my driving is in the city but i barely ever floor it. will changing the air filter make a big difference?

 

how many civics are there on your way to the gas station? lol... i would start with a tune up when i first got my l03 formula was getting about 14 mpg and after a full tune up i was getting 17+ in town

 

Maybe some. Most likely, unless your current air filter is dirty, the improvement will be negligeable.

If you've got the stock exhaust system and catalytic converter, try getting a performance exhaust setup and a high-flow catalytic converter.

Really the best thing you can do is a full tune up if it hasn't been done recently. With a 16 year old car like that there are quite a few things that can do a little damage to your gas mileage, and they can cut it back seriously when combined. Alignment/tire pressure, EGR valve, fuel filter, air filter, distributer cap/rotor/wires/plugs/module, O2 sensor, restrictive exhaust/clogged catalytic converter, etc. A lot of those aren't really that expensive to fix or replace if you can do it yourself.

But, if it's mostly city driving, you're not going to see a whole lot better gas mileage until you get it out on the highway. Driving habits are also a key.

 

U should be able to get around 18mpg in town driving unless your talking stopped in bumper to bumper for an hr at a time.

U prolly have something going south on your car or it is there already.

Get a scanner and see what the sensors read, pay attention to the temp and IAT to see if they jive when cold.

Failing cats could cause mileage to decrease as well.

Or injectors going out, unplug them and ohm them out, they should be aroun 16-17ohms if stockers. GM states over 12 ohm is serviceable. This only checks the electrical side however, doesnt guarantee they arent leaking.

Give it a thourough tune up if one has never been done.

Set the timing and IAC per factory spec.

Tires inflated properly?

Vacuum leaks?

I can keep going but u get the idea.

If your mileage is that bad and your being honest about how u drive, u have something wrong. Check the basics and unknowns first and work from there.