Gas mileage

**Eric1987** · 07-18-2008, 12:48 AM

Does anyone have a clue what symptoms of bad mileage would be? I put 6.6 gallons in the tank and BARELY got 110 miles to it. 30% of that was highway rest was city. My air filter looks good. I'm due for an oil change in around 1k miles. I dunno what the problem is. Unless I do highway I get around 12-14 city if I dont mash on it.

**hmorris7000** · 07-18-2008, 06:04 AM

i feel ur pain its the 10% Ethanol thats added to the gas look at the pump the next time u go Ethanol burn faster than gas so thats where ur mileage is going same here with me i have a 00 5 speed civic that i drive to work b4 this Ethanol stuff was added i was getting 40 mpg now im down to 35 mpg it sucks now my maro im not sure havent driven it in a while gas to high

**daviselk** · 07-18-2008, 06:53 AM

also check your tire pressure, alignment, and your gas cap... all of which are small things you mgiht be overlooking that can def. lead towards low gas mileage.

off topic: what is the stock city/highway supposed to be on a z28?

**1972_Z-28** · 07-18-2008, 07:15 AM

This site is useful for finding stock gas mileage.

http://www.fueleconomy.gov/feg/findacar.htm

**Firebirdjones** · 07-18-2008, 09:28 AM

When was the last time the 02 sensors were changed????

It could be alot of other little things as well that were already mentioned. They add up.

As mentioned,,,quality of gas and octane being used has alot to do with it as well. Climate and elevation can also play a roll.

Your 12-14 mpg around town is pretty horrible,,,, If we are talking about a stock car here...

Both of mine consistently get 20-22 mpg around town, 1 6speed and 1 automatic. They now both have mild bolt ons,,,one even has a smallish camshaft,,,,mileage is still the same with both cars though.

**Firebirdjones** · 07-18-2008, 09:33 AM

I just looked back at your post. Appears you're from CA.
Highest octane as you know is 91 that I'm aware of,,,and I think the blend of fuel Cali uses is 10% ethanol most everywhere???? You may have a hard time finding decent quality pump gas out there. Arizona gets there fuel supply from the same place as Cali,,,and I've been searching around out there with no luck so far.

**Eric1987** · 07-18-2008, 09:37 AM

Well I just picked up the car last month. They said all fluids were just recently changed. I have no idea on the O2 sensors. I filled up with 91. I just put 13 gallons in. I bet I'll have a rough time getting 200 miles outta that IF I can.

**purelsx** · 07-18-2008, 09:51 AM

my 1999 b4c averages 24/26 mpg average, no idea what city or highway may be

**Eric1987** · 07-18-2008, 09:54 AM

Its rated at 17 city 27 highway...

**67CamaroRSSS** · 07-18-2008, 01:32 PM

Normally I get about 15mpg in the city. I found that if I drive and accelerate reeeeaaaaalllllyyyy sloooooooow I can get almost 20 in the city but doing that is boring was hell. This is in the 98 with an M6.

Don't even ask about the 02. I drive it like I stole it all the time.

**daviselk** · 07-18-2008, 01:35 PM

sweet... good link

**Eric1987** · 07-18-2008, 01:38 PM

Yeah I'm only getting comparable mileage on the freeway. I guess its just normal.

**Eric1987** · 07-18-2008, 09:12 PM

Something weird happened. Today when I started my car a weird noise. I was still in neutral hand brake was up. I revved it once and it sounded like a pop. Not a misfire pop but much quieter. And I noticed my inside lights slightly dimmed when I did that. Driving it feels fine though.

**Y2KPewterSS** · 07-18-2008, 09:26 PM

When was the last time you changed your fuel filter? Also, when was the last time you changed your plugs/wires?

**Eric1987** · 07-18-2008, 09:27 PM

Well I got the car a month ago so I really have no clue. Should I do all that? And what would it cost me? My dad said idling he can feel a SLIGHT miss. I told him thats normal which I thought it was but I really dont know.

**Y2KPewterSS** · 07-18-2008, 09:31 PM

Old/clogged/nasty fuel filter will really hurt your MPG and eventually burn up your fuel pump. $15-20 for a new one and very simple to change. Its down around the rear driver tire, just in front of it some.

New plugs would run you $20 as well, but can be a PIA to swap out. Considering your car has over 100K miles, I would highly advise changing both so you know its been done and most likely you will see your MPG increase significantly.

**Eric1987** · 07-18-2008, 09:33 PM

My car doesnt have over 100k. It has 73k. 20 bucks each or for all 8? And can someone link me to a good online store/brand to buy? Wires too.

**Y2KPewterSS** · 07-18-2008, 09:36 PM

Originally Posted by Eric1987

My car doesnt have over 100k. It has 73k. 20 bucks each or for all 8? And can someone link me to a good online store/brand to buy? Wires too.

Sorry, I looked at the 110 in your first post and thought that was the miles

Even with 73k though, I would still change it all out. $20 for all 8

Go to your local auto parts store and get some NGK TR55s for the plugs and search around for MSD wires, Thunder Racing will have them. Wires will run you $50-60.

**Eric1987** · 07-18-2008, 09:37 PM

Why are the wires more expensive then the plugs? And should I change both?

**Y2KPewterSS** · 07-18-2008, 09:40 PM

Originally Posted by Eric1987

Why are the wires more expensive then the plugs? And should I change both?

I can't explain why the wires are more expensive, they just are. Chances are your current wires are probably fine for now. I would change the plugs and fuel filter for now and see what that does for you.