car being sputerish again? hve a question

[SUBBIEEDUDE!]

so usualy i run 87 octane fuel in my legacy but i recent switched over to 93, and i ran about a 1/2 tank, and i filed up all the way and im at 3/4 of a tank and the engine sputters wen driving. and then eventualy stalls out if i let go of the clutch. could puting higher octane gas be the cause of this?

[99SUS SFD]

Why 93? Your car is tuned for 87 and would probably run better on it.

[SUBBIEEDUDE!]

it was running fine on it, i dont get why it would randomly just start sputeringg

[99SUS SFD]

I'm not saying that's the cause, I was just curious as to why you started running it.

[SUBBIEEDUDE!]

oo i heard it was better to run higher octane

[99SUS SFD]

Not if your car isn't tuned for it. You're essentially just paying more per gallon.

[SUBBIEEDUDE!]

yah truee, im thinking its the gas. so how do u supose i get the gas out? besides using a syphan pump

[99SUS SFD]

3/4 of a tank is a lot to take out too...hmm, dunno. Maybe if it's just water in the tank you could get some dry gas.

[SUBBIEEDUDE!]

hmm. ill take some out and put reg gas in. ill see if that works

[Sarra]

That's what happens when I run 87 in my WRX, it just goes "WTF?!" and sputters, won't make boost, and misses at idle.

Just run 87, or if you have a tired, old engine, 89 mixed with 87.

[outbacktweaked95]

if its water that wont help id go with 99SUS ive had a couple of cars with these problems and all u need is a bit of drygas and everything is fixed

[SUBBIEEDUDE!]

dry gas is 87 right?

[Huffer]

It might be unrelated but you could very well have a clogged fuel filter or misfiring injector. The injector should throw a code, but the fuel filter won't.

I would remove as much of the 93 octane as possible and refill with 87, and throw some Seafoam in the tank...

Could also check your fuel pump.

[99SUS SFD]

dry gas is 87 right?

No dry gas isn't "gas" at all, it's an additive to the tank.

[Reason]

I run 93 octane when I use seafoam or injector cleaner and I have no problems.

I would add a can of seafoam, change the fuel filter. If it is still a problem it could be the fuel pump. I had this problem with my SS.

Running 93 in your car isn't the problem at all.

It's a problem when you run a lower grade in a turbo car, not the other way around.

[decke48]

dry gas is 87 right? dry gas is pure ethonal.. it will raise the octane rating some maybe .1-1 point

[98BG5GT]

The sputtering could be an affect of clogged injectors, fauled plugs, and/or bad sensors, or most likely something mechanical like an EGR valve. Usually pump gas will not cause an engine act the way you described. The Seafoam treatment can't hurt. It's mostly just a thin oil, solvent and isopropanol and has better results than Drygas. If you still have this problem, can you describe it in more detail?

[decke48]

ahh good point bg5gt. it could be the egr sticking open. subbie what kind of station did you fill up at. a no-name or known-name?

[SUBBIEEDUDE!]

i got the gas at cumberland farms i believe. an recently hasnt been doing it. i got some fuel system cleaner and put that in today, and its been drving great. but it recenty did the same thing a couple months back, and i got a cel. MAF or MAP input to low, and i got that CEL the other day again. and when i clear the code it seams to run fine. hmm?

[98BG5GT]

The check engine light message is helpful. Here are some tips you can try to troubleshoot your "MAP" manifold absolute pressure sensor, this is located on the passenger side on the strut tower facing the air cleaner. The part itself has a 3 wire connector, and a single vacuum hose coming out of the bottom side. The part is about 1 1/2 inches wide and utilizes 2 mounting bolt holes. Some MAP sensor problems are not the fault of the sensor itself. If the vacuum hose that connects the MAP sensor to the intake manifold is loose, leaking or plugged, the sensor cannot produce an accurate signal. Also, if there is a problem within the engine itself that causes intake vacuum to be lower than normal (such as a vacuum leak, EGR valve that is stuck open or leaky PCV hose), the MAP sensor's readings may be lower than normal.
The "MAF" mass air flow sensor is located on the intake piping assembly right after the air filter. The sensing element in MAF sensors can be easily contaminated causing hard starting, rough idle, hesitation and stalling problems. Cleaning a dirty MAF sensor with electronics cleaner can often restore normal sensor operation and save the cost of having to replace the sensor. If you use an aftermarket air filter like K&N, which are saturated with oil can accumulate on the sensor filament causing it to read low circuit inputs. If you need to replace the sensors, get Subaru oem only.

[SUBBIEEDUDE!]

this is very good information here. and maybe my problem. ill look at it tomrorw. thank man