Hello Subaru people!! I have a 1997 Subaru Legacy Outback that is misfiring on all cylinders and I have gotten it scanned and that is all it tells me. I Have already replaced the spark plugs, spark plug wires, and ignition coil. I am going through an extreme amount of gas also. I have to fill her up almost all the way when I go to work which is about 20 miles away from where I live. When I am stopped it idles real low and then when I press the gas pedal down to the floor I hardly go anywhere and the all of a sudden I jump from 2,000 all the way to 4,000 and take off. Also if i am trying to park and i cut the wheel to much she stalls. Thanks for all the help to anyone that can. 

Edited May 26, 20169 yr by owen8898

Also I have went mudding and my exhaust pipe broke at a weld and i dont have a welder to weld it back togther. It broke right after the First catalytic converter I believe. Every since it broke the misfireing started. 

You know that it is Hard to diagnose a fail on an engine that I can not see, hear or test by myself; and I'll like to know if the engine has a clean / new air filter's Element; and also it is important to know \ see, in which state came out the old sparkplugs: they actually tells a lot of information from the Engine's combustion behaviour.

 

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Assuming that they came very Fouled, plus the fact that the engine is using a Lot of Gasoline; I believe that there should be a Bad amount of carbon deposits / sludge buildup on the Combustion Chambers, and the Valves' necks; Besides that, the engine might have dirty injectors, and also a Failing IAC valve, plus a dirty MAF.

 

In that case, a good Cleansing of the injectors, plus a Seafoam cleansing for the Upper Engine / combustion Chambers and Valves, along a Cleansing of the MAF / IAC valve might take care of all those problems...

 

But also it worth checking the Exhaust system, in order to establish if there is a Clogged Catalytic converter(s) or Muffler, in combination with the rest of above stated probabilities.

 

Kind Regards.

Check to see it your o2 sensors got damaged.

Check to see it your o2 sensors got damaged.

A bad O2 sensor could cause extreme gas consumption and the flooding would cause misfires. It would be a good place to start.

The crack in the pipe is your problem, its letting air in cooling the front 02 sensor making it change the fuel air mixture.

 

Get the crack welded up and you'll be good to go

I have a 02 legacy and I am having the same problem and have done everything you did and its starting to be costly!! i am not having the fuel problems but i do not have a crack in my pipe doubt it has anything to do with it tho i am sure it is something electrical but plugging in the diagnostic machine is wayyy to expensive

I have had good luck with Techron, I would overdose with two 20 oz. bottles to the tank. Also is your crank gear pulley solid? If things are lose in that area the woodruff key enlarges the pulley slot/crank key way and the timing comes off resulting in misfires.