2005 Subaru Legacy Engine Problems...

[ZachE84]

Hey all.

I bought a new car about 6 weeks ago. All was great until my friend borrowed it for a trip 100 miles round trip. Come to find out, he put in 87 gas. 92 or greater is not reccommended, but required. The engine is getting worse and worse. I called Subaru right away and they told me to put some octane booster in and to wait until I fill it up 2-3 times with 93. So 3 gas tanks later, the problem is worse. Acceleration has gone down and the pinging is so terrible.

I took it to my dealership this morning and the mechanic asked me whats wrong with it. I told him simply it had heavy knocking, pinging and the acceleration is worsening drastically. Guy was a, well...anwyays. They callled a little while ago and said nothing is wrong. Now im no expert, but when I first bought the car and up until that night my brother put 87 gas in, I could never tell if my car was on or not - not now.

Someting is wrong with it, but who would know better than the Subaru Dealer? I guess ill have to check some things, air filter, etc, etc.

Any suggestions? Thanks.

I think my next step it to take it to another dealer and let them hear the sound of a new Legacy and then let them hear mine, which only has 2K miles.

[Polygon]

Check your spark plugs, they could be fouled. Also, bad gas can cause problems with the oxygen sensor.

[ZachE84]

Cool, thanks. Do you think resetting my ECU might help?

[Polygon]

That is always worth a try. However, I've heard of new cars where if you unplug the battery you have to take the car to the dealer to have the ECU reset because the car won't start.

[RandomTask]

I wouldn't imagine that being the case, if it were, then the car wouldn't start after a dead battery. If the car is brand new, insist the dealership take a look at it, everything should be under warranty. I wouldn't know how plugs could foul out that quick, but its worth a shot. Do you know what kind of driving your friend did?

[bjdm151]

If you have a check engine light or service engine soon or whatever Scoobies happen to say, take it back to the dealer and ask them what the code is. It sounds like this type of drivability complaint should have thrown up a code that needs to be checked and fixed.
Just another thought that occured to me. Unplugging your battery should reset your computers writeable memory (RAM?) THis is the memory that can slightly modify fuel and timing maps to your specific driving habits. The 87 octane might have forced your computer to set the timing way back and increase injector on time. If you do this, and for legal purposes i'm am not sugesting this, it should set it back to your ECU back to stock parameters that come off of your read only memory.

[383PhoenixAm]

I have no idea why Subaru would....blah

There is only a small chance that all this bad stuff is being caused by the computer, and resetting it certainly isn't going to do much unless that was another one of Subaru's innovative ideas. Putting lower octane than needed is a sure way to knock an engine to death, and that's probably what happened.

This is just hypothetical- I don't know how Subaru engines work. Say that Subaru included a knock sensor in its array of engine sensors (which would make sense.) If this sensor detects any kind of knocking or junk like that it will cause the ECU to retard the timing waaaaay back, and that's a good way to lose a lot of acceleration. Is the engine timing good?

[jimmy[the]gent]

just rev the shit out of it in neutral or park

tuff love

[Rufe]

I strongly suggest you go to a Subaru dealer where a senior service tech will drive in the car with you around the block. This should be all you need to do. Don't accept any less.