I have a problem pertaining my gas mileage. I have searched but don't know what could be wrong still.

Here Is What I have replaced

Front o2 Sensor
Spark Plugs
Wires

I have a heavy foot sometimes but I dont think it would cause me to get 200miles a tank, which averages out to 16mpg for me this is city driving.

I see oil around my EGR valve, is it possible its shot? I am curious as to what kind of difference that makes, because I know they make an EGR block-off kit and If mileage suffered that bad without it I dont see why they would make one. Anyway, is it possible that it could be going dead and just not be shooting a code? What does it cost to get this replaced? My car has 97K miles

If someone can respond to this a.s.a.p I would greatly appreciate it.

I had issues with mine, even after I changed the o2 sensor. I unhooked the battery, touched the two leads together (for what reason, i dunno), but there weren't connected to anything, I guess to ground out any caps or something :shrug

While the batter was unhooked, I put a new sensor in (went back to vatozone and swapped it out). It worked fine after that.

The reason I unhooked the battery and shorted the leads was because when the motor was running, I wasn't getting anything from the o2 wiring harness. Not even the power from the heater wire, as though the ECU sensed something was wrong and turned it off, I dunno. After I left the battery off for a while, hooked it back up, everything worked fine.

I have tried that before didnt see any results

you make short trips? that kills fuel economy, lotsa energy is wasted heating stuff up to operating temp, then arriving at your destination.

Someting is def wrong. Finish up the tune up. do a fuel filter if you havent already. IF you have access to a Datalogger or scanner check to see what the O2 counts are? Also check to see if you have a leaky injector, that could do it.

When you changed the Plugs what did they look like? color?

Terry

Definatly check for leaky injector, i had a problem with my 95gs only got like 220 miles to the tank replaced o2, egr no change, than i noticed if i drove with the windows down i smelled gas really bad, discovered a leaky injector, fixed it and gas milage went up to about 300 a tank, i now have a 98 rs and get anywhere from 300-350 a tank.

The Plugs were a brownish color but were of pretty normal wear not burnt away or corroded. I don't have a leaky injector, I would deffintley smell it If I were plus I looked at the fuel rail and didnt see or smell it. Question about this EGR valve though because this looks in bad shape. Is this valve suppose to open all the way? It only pops open a lil bit.

Not sure if this helps or not but i removed my egr and the difference in gas milage was very minute at times i dont even notice a change, i remember hitting like 330 per tank when i had it on but that was like rolling into the gas station on dead empty mine crapped out so i just took it off, seriously doubt your egr is killing your fuel that much, and if your plugs were brownish than theres no real sign of running rich so there goes that hope you figure it out. what kinda gas milage were you getting b4.

I have owned my car for over a year and ever since I have had it, I have never been able to break 200 miles a tank filled to 12-13 gallons. Maybe if the EGR valve is dirty and doesnt work correctly it causes more harm than just blocking it off all together. All I know is that it dirty as hell around there on the head. Maybe tommorow night I will fuck with it.

Oil is not good around your EGR valve. I know that if you block it off with a plate, you will get to see oil. It's something to do with the vaccuum between the exhaust and intake manifolds. If they don't have the same vaccuum, oil seeps - not good. My recommendation, don't block it off and don't replace it. Purchase a catch can so that you get the best of both worlds.

ive got a 17 gallon tank in my car that might be the difference however you should get more than 16mpg either way, its possible your sending unit might not be working correctly ever run out of gas?? i dont know im just throwing things out here but from what your describing id say you have to have a leak somewhere, my old car would only leak while i was driving, and somehow the gas was evaporating so at idle or even while it was sitting off no aparent leak. sorry dude let me know when you figure it out

Nope, never leaks ever.. And I leave my car running and sit outside of it often talking to people and I never have the problem. Fuel sending unit is good, I have never run out of gas. And how the hell do you have a 17 gallon tank? God that must be a bitch.

I also want to point out that my car does not run rich, and that my compression is 180 on all 4 cylinders.

all 1990-1996 eclipse models have a 15.9 gal fuel tank when full, 97,98,99 have a 17 gallon tank but not to get off topic here id go with what the last guy just said he seemed to have a better suggestion than me sorry i couldnt help

Originally posted by EclipseTenzoR
Nope, never leaks ever.. And I leave my car running and sit outside of it often talking to people and I never have the problem. Fuel sending unit is good, I have never run out of gas. And how the hell do you have a 17 gallon tank? God that must be a bitch. I also want to point out that my car does not run rich, and that my compression is 180 on all 4 cylinders.

you have a 17 gallon gas tank too.
its fucking huge, i know. (galant commonality working for us again?)

My tank is 13.5 gallons roughly.. Anyway enough bullshit about the gas tanks. Need a solution to mileage. I took out my EGR today and cleaned it up good. Have no idea if its going to make a difference but there was alot of shit I got out of that thing with brake cleaner. I have been easy on the gas so far, so we will just have to see how it goes. If it does'nt work out, I may just take it to satan to fix. Gas is to expensive for me to be getting this kind of mileage. Also, I thought rear o2 sensor was just for emissions? Keep it coming guys, any other info is greatly appreciated for myself and others who have this problem.

Also as for my driving habits.. I am an automatic and for this tank so far I don't go over 3500-4k when the car shifts. Is that alright to go that high and still try and retain decent gas mileage or is it pushing the car hard still?

Originally posted by EclipseTenzoR
I took out my EGR today and cleaned it up good. Have no idea if its going to make a difference but there was alot of shit I got out of that thing with brake cleaner..... Also, I thought rear o2 sensor was just for emissions? Keep it coming guys, any other info is greatly appreciated for myself and others who have this problem. Also as for my driving habits.. I am an automatic and for this tank so far I don't go over 3500-4k when the car shifts. Is that alright to go that high and still try and retain decent gas mileage or is it pushing the car hard still?

That EGR valve may have had enough crap in it to be sticking open. Even if it was slight, that would allow the fuel charge going in to be continuously diluted with exhaust.... (I hate EGRs) and it will effect mileage and driveability.
Someone can correct me if I'm wrong, but I believe the rear O2 feeds the closed loop circuit as well as the front and both are for "emissions".
Just let it shift by itself and try to stay off it as much as possible.
Check your tires and make sure they're air'ed up good.

How do I know if it is stuck open? I see the rod with the plate move down ever so slightly when I rev the car, but other than that the plate inside of it stick firm up at tht top. Can't really explain it, but is this valve suppose to have a long range of motion?

Originally posted by EclipseTenzoR
I have a problem pertaining my gas mileage. I have searched but don't know what could be wrong still. Here Is What I have replaced Front o2 Sensor Spark Plugs Wires I have a heavy foot sometimes but I dont think it would cause me to get 200miles a tank, which averages out to 16mpg for me this is city driving. I see oil around my EGR valve, is it possible its shot? I am curious as to what kind of difference that makes, because I know they make an EGR block-off kit and If mileage suffered that bad without it I dont see why they would make one. Anyway, is it possible that it could be going dead and just not be shooting a code? What does it cost to get this replaced? My car has 97K miles If someone can respond to this a.s.a.p I would greatly appreciate it.

Well, there is certainly something not right....mileage should be better than that. I would think that IF the EGR were stuck open due to crud etc., mileage would be hurt somewhat with the dilution of the intake charge, but the car would run like crap too...I think you'd notice it.
The O2 sensor(s) will have a direct effect on mileage...big time. Not sure if your car has a post cat O2, but change it too if it does. Granted, the O2s only come into play (mileage-wise) in "closed-loop" ie: car is at operating temperature, high gear and is at cruise (not hard acceleration etc.) They can account for 2-5 mpg gain.
As previously stated, short trips will kill mileage. A heavy foot will kill mileage. Under-inflated tires will kill mileage. Wrong-sized tires could kill mileage. a plugged, or partially plugged cat converter will kill mileage (would run terrible too). You've already changed plugs etc., so that is not an issue. As an example of how different drivers can affect a vehicle's mileage: My wife can drive the 420A-equipped car back/forth to work all week and get 30+ mpg consistently. My son can drive the exact same car to school all week and barely get 25 on a good day....and he says he doesn't have a "heavy foot"...go figure. Granted, hers is all highway stuff and his is a little of both highway/city.
I would clean up the EGR and ensure it's working or blocked off. Replace the back O2, if so equipped and make sure the cat isn't plugged up. Keep good inflation in the tires. Drive as if there was a raw egg under the gas pedal. :) See what happens.

have you checked your compression yet?? shitty compression will screw mileage too
doug

My Compression was 180 on all 4 cylinders.

I am curious on what everyones driving habits are. When do you let the car shift? At what RPM. I use to let it shift at 4500-5000 because our cars are ungodly slow stock and take forever to get going with the low end power.

I wish I could help give you some direction, but U peeps prob know more about improving it than I do... the better the gas mileage the better, especially if gas prices are supposed to hit $3/gallon in South Florida by the end of the year.

Anyways, I posted this just for you :afro
http://forums.2gnt.com/dcboard.php?az=show_topic&forum=5&topic_id=88278&mode=full

- J