gas mileage problems

[dorkins]

searching didnt help, and the other thread i posted in seems to have been trimmed down...

i have a 98 3.8l camaro

tank 1- 87 octane, 180 miles to the E line, so about 13 gallons... about 14mpg

tank 2- 89 octane, 220 miles to the e line... about 17mpg

tank 3- 87 octane with fuel injector cleanor (cheap stuff at napa) 280 miles to the e line... about 22 mpg

tank 4- 87, 190 miles to the e line... about 15 mpg

tank 5- 87 with stp injector cleanor, with techron, 310 miles to the e line... about 24 mpg

car has 58k miles on it, second owner, great condition... and the car reads about 190* (stays exactly at the 1/4 bar)
and, i live in northeast ohio... so its cold

[V8 Killer]

City Driving?

[dorkins]

60/40 highway/city

[V8 Killer]

lol,thats some pretty horrible mileage then.

[dorkins]

thanks for all the help...

[V8 Killer]

Motor tuned up?
Tire Press good?

[dorkins]

car is stock tuning, stock everything but has smooth air lid...

[Th3 RiCk]

It's time for some: new plugs & wires, fuel filter, air filter, and I think it's recommended to change the o2 sensors after 30k miles (Someone correct me if I'm wrong.) Believe it or not, correct tire size and pressure will change your gas mileage.

[dorkins]

i was planning on gettin a k&n in spring... so i guess ill do it all in the spring...
how much would that all cost? and, what kind of plugs and wires should i get?

[V8 Killer]

Just get regular AC Delco Plugs/Wires

Plugs/Wires-$20
Air Filter-10$
Fuel Filter-$10
O2 Sensors-Variable

TH3 RiCk is right,O2 Sensors and Tire Size/Pressure is a major factor.All those parts will dramatically increase your mileage.

[Th3 RiCk]

I wouldn't imagine any more than $50-$100 depending on what you get.

You could pick up a set of 8mm Taylor wires from Thunder Racing (A sponser of the site, and they usually have a lot of sales throughout the year). They'll run about $40 bucks. AC Delco wires are pretty cheap, around $15 I think. You could get NGK plugs or any other manufacturer for that matter for $15.

K&N Air filter is about $50. But it also never needs changed again.

The fuel filter is also based on how much you're willing to spend. You can pick up a stock one for around $10.

O2's get a little pricey though. I think they're around $30-60 a piece depending on the manufacturer. You can pick some up online, like Autobarn.com or GMPartsdirect.com. Advance Auto or Autozone should have them too.

[ March 01, 2005, 02:05 AM: Message edited by: Th3 RiCk ]

[dorkins]

how many o2's are there to replace? and where are they located?

[38fury]

Two in the exhaust manifolds. They just basically read how your engine is burning, by detecting how much oxygen is in your exhaust and adjusting injector pulse.

[dorkins]

all i have left to do is o2 sensors and plugs and wires

i still dont seem to be getting any better mileage after replacing fuel filter, pcv valve, air filter with a k&n, oil change

will replacing the o2's and plugs and wires help more?

[terminaldegree]

Originally posted by dorkins:


will replacing the o2's and plugs and wires help more?

I think they would help more than anything else you've changed so far. If you ever figure out what it was, post back here so we know.

BTW, I disagree that people with good running cars need to change out their o2 sensors every 30k. My fuel mileage with 42k on the originals is better than EPA. Heck, my mileage on a 172,000 mile Oldsmobile 3.1 was darn close to the EPA figures when I sold it w/ the original o2's still in.

Even dealers that are trying to rip you off aren't putting those on the list of "recommended services" at that mileage.