I have a 98 montecarlo z34 and being pretty nice on the car i get about 280-300 miles a tank and i think i should be getting more than that, the plugs and wires are original and have 104k on them and i'm pretty sure that will help, i already replaced the fuel filter anything else i can do? thanks

 

Bad Gas - take a TUMS!!!!

Seriously, I would change the plugs and wires as you are probably getting weak spark and loosing power as well. 300 is about right on a tank of gas for city/hwy. I would actually fill your tank to max. Drive. Next time fill up to max again. Take the miles you drove and divide by gallons put in tank.

This will give you your milage and it should be in the 26-32 mpg neighborhood.

 

i do a little better than that on my 03 SS, but not much better. i can get about 325-350 if i'm lucky

 

Ohhh. Change your air cleaner to a K&N drop in filter for about $40. You will never need to buy a new one and it will improve milage.

 

Get an injector service also?

 

A dirty air filter can definately affect your mileage AND how cool the engine runs.

Ask me.

 

Take the crap out of your trunk and make sure your tires are properly inflated. An easy 5% increase for me.

Another on for space. Bodacious!

 

pah, i put in a K&N, didn't see a dang bit of difference. maybe the FIPK kit will do something, saving up for that now.

 

I've got just the drop in K&Ns in 3 of my cars. I like them.

 

Yes, and don't always run with your tank full..what, 17 gallons of gas weighs about 300 lbs.

I always keep mine at a quarter tankand I keep my trunk empty.

That should also get you a few percentage points in mileage.