horrible mpg 4-12 miles per gallon no cel

Ok I got 96 legacy ls 2.2 auto and my mpg is way below normal I run 91 always. Im never on highway so this is city/country driving. I have uel header and maf adapter w cone filter on my stock intake tube ngk irridium plugs and ngk wires. Run Mobil 1 full syn oil. The cel works I know for a fact. I noticed low rpm it kinda kick ups then rips fine. And other day some idiot almost hit me at a stop sign and i put my foot to the floor to get out of the way And car almost stalled out just kept goin from 1.5k rpm to 200rpm and then took off. I have replaced all fuel lines, filter, vacuum lines, coil, both o2 sensors and only use OEM parts. And i did all new grounds AMD ground strip and added cpl more grounds cuz I was having voltage problem at low rpms for a lilwhile this salty new York winter. Ive taken it to suby dealer n they say everything is fine ive taken to my buddy's work hooked it up to there scanner to read ecu monitors n what not and everything's good from what my service program says but I know theres something wrong. And if one more person says just put fwd fuse in and run it like that for better mpg needs to be shot cuz its impossible to get better mpg in fwd unless u totally delete all rear drivetrain to get rid of the dead weight thats usually helping the front out. Ive tried it and got way worse mpg and I know its not good for it I just wanted to find out myself. I use this car for work right now and its costing me 40-50$ to do 120mile route. I actually get 1-2 mpg better when I flip it into sport mode w mod I did myself. I have a 98 legacy parts car im using as donar for my 5 speed swap later when i get time. I just need better mpg and cant pay dealer a million $ to fix everything in the car thats already been done or nothing at all my old wagon got 20-25 depending like I might as well be driving v8

From my experience the fwd fuse is for diagnosis only and you should keep a fuse in there for everyday driving. Plus you won't see much of a mpg gain because the rear diff and axles will still be spinning and the weight of those parts. There would just be no power going to the rear.

well I would get Torque app for an android phone or tablet, and the Adapter off Ebay search "OBD Bluetooth adapter" Get that install it and set the app up so you can monitor your short and long term fuel trims.

 

This will tell you if the car is dumping a bunch of extra fuel or not. From your above post everything has been changed except the oxygen sensor. with the torque app you can also see the 02 voltage and determine if it is functioning properly, it should normally fluctuate I can't really explain it as I don't know 100% but the information is online...

 

easier to take the 02 from your parts car and swap it over. also could be a restricted exhaust (catalytic converter likely) making it harder for the vehicle to breathe. Or leaks in the intake hoses. - This will be apparent by long term fuel trims that are over 10% the car is dumping more fuel to make up for the extra air that skips the maf and the oxygen sensor realizes and corrects the issue.

Buy the ELM 327 Bluetooth adapter

The elm 327 a good one zues? Ive been thinkin aboutpullin the triggeron one but I always end up buying another sticker....

I've had that one for a year or so now, it works great and its small enough that I just leave it plugged in all the time and dont even notice

From my experience the fwd fuse is for diagnosis only and you should keep a fuse in there for everyday driving. Plus you won't see much of a mpg gain because the rear diff and axles will still be spinning and the weight of those parts. There would just be no power going to the rear.

 

 

Spoolin30 i already said that and actually u never want fuse in cuz when its in its in fwd....

Both o2 sensors were changed w OEM ones cpl times now. Only thing fuel or air related I have yet to change out is sending unit. I have noticed a random fuel smell that comes and goes no leaks tho. This weekend I put new tierods inner and outer on and ball joints wheel bearings and did alignment. I did put 16" 2.5i wheels on it w 205/50 for tires my stock wheels have snows on em and there 15" and bigger in diameter then my 16"s w tires. So elm 327 v1.5 mini is one i want

Hello;

A few things come to mind on gas mileage, things to check. Fuel pressure regulator, check vac hose for gas. Plugged exhaust system, my muffler was clogged along with converter. How's that filler neck on the gas tank? Any gas leaks, does the fuel pressure hold? Just a few thoughts, Steven.

i have this one

http://i.ebayimg.com/00/s/MTAwMFgxMDAw/z/RRkAAOxyJX1TEA7P/$_12.JPG

 

and it works great.

 

btw, i didnt see what your mileage currently is, is it lower than 20? lower than 15? no other codes at all? it sounds like you have other issues, if you stomp the throttle and it drops to 200 rpm and wants to die before getting up and go.

Keep the fwd fuse out

Buy three or four of the Bluetooth adapters they are 10 bucks shipped and ive had 3 of them choke out on me so far... one died on arrival

^gotta get the elm 327 man! lol

Ok I tried posting a video of it but says security problems lol dunno why guess it doesn't like droid. I did post a video on instagram @rybrown21 check it out. And again I have replaced every vacuum line, fuel line, and no cel, o2 sensors have been changed runs different w New ones or old ones in it, cats seem clear and fine, muffler def isn't plugged like someone mentioned cuz its a "fart cannon". And it only does the stalling deal when its warm. I ordered elm 327 mini v1.5 and purchased torque app.

Ok so I got a code the night for catalyst below threshold, and cpl 1-2 misfires.New plugs with coil. since both sensors are new I took cats off n sensors out and there was gas on the sensor and in front cat not a lot but was def wet. So took cats off my parts car that runs fine. Put same sensors back in and put stock intake back on reset ecu and went 300 yards and car was just as bad as before. No change at all switched in new sensors reset ecu same thing no change. Could itbe stuck iinjector this is driving me nuts and costing me lots of $. The past cpl weeks its got progressively worse

If ur parts car has known good injectors u can try swaping them

Switched injectors today no luck same shit different toilet. My buddy didn't believe me about this problem andhhe checked it out and doesn't know either. Hes a mechanic at a dealership. And has 2 legacys a 98 and 99. Its so stupid I ended up buying my old car back haha a civic hatch I never finished. Its fun to drive and way better mpg then my legacy and it runs great and its fun to drive. But yea any more ideas would be great and still waiting on my elm 327.

Update. Still horrible mpg so I got a code p0420 New cats and new sensors so def not that. Changed spark plugs today and temp sensor reset ecu still Shitty.

what brand of sensors?

Denso o2 sensors ngk plugs

ok still chasing this and still have code p0420 car is still running super rich, did compression test all four cyl at 175-176. people say its the uel header but it did this before the header. i deleted the egr 2 see if maybe it was that no change, changed coolant temp sensor, tried another maf sensor, checked timing, thats good. cpl times last week when engine and trans completely cold at trans temp light flashed on start up. things i have yet to replace tps sensor, iacv, fuel pressure reg. and at dead stop go to 3/4-full throttle to take off and cuts in and out still

Might have a bad ecu, ask your buddy if you can plug one of his into your car. It's not a common problem but not unheard of either. That sounds like way to many swings with misses and a lot of problems all at once.

Probably spent more than I should have, but I bought this one a few years ago and it's still workin' great.

 

http://www.obdkey.com/

the ELM 327 bluetooth obd reader and app called 'torque' will do many of the readings for $12..

 

swap out the IACV lately? the UEL header isnt the issue

Im switching ecu in am and have yet to check iacv, did unplug it and it stall immediately. I have elm n torque whats vacuum pressure at idle on yours Zeus. Could tranny be sending faulty signal to something changing way its running cuz I have full 5 speed waiting to go in but dont wanna do it until know motor is running good

ok still chasing this and still have code p0420 car is still running super rich, did compression test all four cyl at 175-176. people say its the uel header but it did this before the header. i deleted the egr 2 see if maybe it was that no change, changed coolant temp sensor, tried another maf sensor, checked timing, thats good. cpl times last week when engine and trans completely cold at trans temp light flashed on start up. things i have yet to replace tps sensor, iacv, fuel pressure reg. and at dead stop go to 3/4-full throttle to take off and cuts in and out still

 

i dont see that you changed the rear o2 sensor. the 420 code can be caused by a bad o2 sensor, which will make the engine run richer. i have had that issue on a couple vehicles, the latest was my 01 dodge ram truck. sucker went from 16 mpg to 7mpg. changed the rear o2 out and it went back to normal.