Curry

iTrader: (1)

Ok I need to start narrowing down what's killing my gas mileage. I decided to put together a checklist to see whats causing it.

I do mixed driving and im only getting 9-10 mpg!!!

Car is still lowered but I am back on stock wheels.

Step one... I took off the 20's and emptied my trunk. Mileage has not changed.

So far here are the things I NEED to check.

-Alignment
-Plugs

Anything else? I have no CEL's

Would a bad o2 not show up as a CEL and cause problems?

swat1727

iTrader: (2)

yes bad o2 sensor will show up on CEL. i would say clean ur mass air flow sensor, clean ur throttle body, fuel injector cleaner, flush ur tranny, engine oil, air filter. that's all i can think of rite now

ThomasGS4

iTrader: (19)

I think it could also be the spark plugs.

(correct me if I'm wrong)

Rock-a-Lex

iTrader: (4)

Yes, check those items and all other previously mentioned by the other members. Something has to be going on there. Also, I know this may sound stupid but are you putting premium fuel in it? Try some Techron fuel injection cleaner or even Lucas fuel injection cleaner.

BTW, your car looks great (in your sig)! I said it before and I'll say it again...those tails looks nice on your ride MUCH better looking than when they were on my car; I guess it goes with the VIP route much more.

tmf2004

iTrader: (15)

I would start with the fuel cleaner like Rock said and probably the plugs if they never been done before. Also do the MAF sensor and TB clean...

UncleRay

iTrader: (2)

Clean your MAF sensor?
Clean your throttle body?
O2 sensors changed?

NemeGuero

iTrader: (15)

new Plugs, new air filter, Fuel Injector cleaner, and yeah oxygen sensors.

KingNasGS4

iTrader: (22)

what part of NY do you live? because If it's NYC, its not going to help.

I asked this same question a couple months ago, and a few other members from here in NYC said its NOT going to improve. due to the stop and go traffic. and they got low MPG #'s too.

BUT still maintain your car right even if you won't get better MPG

Infamous 1

iTrader: (20)

i think swat covered it!

epic1si

gotta agree with the others here...i have a gte swap and i get like 15mpg mixed driving then again i'm hammering it half the time too

BinaryJay

I get an average of between 20-22 mpg at the end of the tank, I don't do much highway driving. The best I saw once was when I went for a highway trip after filling the tank, when I got to my destination it was equal to about 29 mpg.

OOps... I didn't realize I was in the 2gs forum. I own a 3gs. I'm sure my comments don't help. :|

Curry

iTrader: (1)

Thanks guys I'm going to start doing those things tomorrow and see what happens. First things first.. Im doing my inner tie rods then getting an alignment.

I did change ONE o2 and that was because I got a CEL. Should I change the rest anyway?


Thanks bro. I do get a lot of questions about the lights. lol. Much props to your work... I have yet to see them leak!! Sig is old... I have new wheels and a lower drop.

Oh and yes I am using premium fuel. I have used a bottle of STP cleaner already didn't see any difference. Maybe a different brand of cleaner?

I am in queens but I know 2gs owners that are getting 18-20 mpg right here in queens and brooklyn. There is no reason I should be getting 10mpg with STOCK wheels. Something went wrong somewhere.

Rock-a-Lex

iTrader: (4)

Curry,

If you decide to change ALL O2 sensors buy them at sparkplugs.com. Trust me...they don't just sell spark plugs! Their O2 sensors are by far the cheapest around! They have OEM Denso O2 sensors made for our cars for around $85/ea...I remember about 6 months ago I replaced all of them for around $350/shipped! The dealer (including Carson) wants anywhere from $220-$250 for EACH O2 sensor. Check out that website!

Also, the STP stuff is junk...try either Lucas or Techron; it makes a BIG difference. Also, Lucas I believe lubricates the upper engine components as well.

Curry

iTrader: (1)

If I go with changing all my o2's it will be at the end if the other things dont work. When I did change one I had bought a universal denso for like 52 bucks and it seemed to work. No more CEL. I doubt that could be contributing to whats going on.

I'll pick up a bottle of lucas today and try that.

Any suggestions on sparkplugs? NGK's from autozone are fine?

98GS300-2

Despite what everyone says, including the owners manual, I have gotten better mileage and performance with single electrode plugs vs dual electrodes. I had duals in and every time I started it I could hear some knock it sounded like while it sat an idled. I threw singles back in and that went away, also had better throttle response and about 1mpg increase.