ONLY getting 11.6 Miles per Gallon??? HELP

[Brandnuflavor]

Hey guys my cars been acting up real bad. I am wondering if you guys could let me know of some things that could be wrong. My car is jumping from 1000 to 700 rpms when idle and I can hear the engine rumble from time to time. My gas mileage is REALLY Bad. I am only getting anywhere between 11-12 miles a gallon. I dont know what to do. My only upgrade is a Greddy SP Cat and boost gauge and turbo timer. Thankyou guys very much in advance. btw ( 98 eclipse gst auto)

 

[spyderturbo007]

Do you have a logger? If you do take a look at your FT's and you O2 voltage at idle and let us know what you find.

 

[Brandnuflavor]

please forgive my ignorance, what is a logger? thanks

 

[L2RTSiAWD]

Moved to the newbie forum.

A logger is a device used to monitor engine functions.

www.pocketlogger.com is a more popular one.

 

[L2RTSiAWD]

How many miles are on the car.

The O2 sensor is probably shot.

 

[Brandnuflavor]

Yea thats what I was thinking, it has 109, XXX miles on it. There are two O2 sensors right?Umm would it be the O2 sensor in the front or the one in the exhaust?

 

[L2RTSiAWD]

The front one.

 

[Brandnuflavor]

Cool thanks man. Im going to take it to my DSM shop and have them check it out for me. I appreciate all the quick responses. Thanks guys!

 

[Alex_95TSI]

I have same issue but i cant get my damndid logger to connect ARGHGHGHGHG

 

[xveganxcowboyx]

I hae pretty much the ame problem + lack of power. I'm pretty sure mine is the TPS. It would be worthwhile to check that as long as your testing things.

 

[GSX0TIC]

I was having horrible gas mileage just like you were until I just replaced my spark plugs, wires, changed the oil, and replaced my upstream o2 sensor...my car only has 71k miles on it and my upstream o2 sensor was shot...$100 for a bosch o2 sensor from autozone.. it's most likey the problem for yourself.