Howdy all,

 

First time Subaru owner. Bought my son a 95 Legacy L FWD with 204,000 miles on it. Ran like a top for the first couple months, now it has an increasingly annoying issue.

 

He warms it up 10 minutes before driving away. Still, the car will randomly bog down when he hits the gas. Then it may give it little bang-pop and take right off. Or it may stall. I have a hard time making this happen because it happens less and less as the car gets warmer.

 

We replaced all the plugs and the wires with really good stuff. We changed the oil for high mileage synthetic stuff. We even changed the fuel filter.

 

The problem is getting worse, so says my son. ALSO, the gas mileage is for crap now. Either that or the sensor in the gas tank has lost its mind.

 

Any ideas what I should be checking?

Sounds like a bad front oxygen sensor for starts.

 

Any check engine codes?

Problem with it being just the front O2 (which could be a possible source of the crappy mileage) is that the front O2 is ignored by the computer till it gets hot enough to start reporting - which occurs at approximately 600* F. If the problem gets better as the engine warms up then the sensor is probably ok because that's exactly the time that the ECU would begin using the sensor for it's fuel calculations.

 

I would say that you need to test the coolant temp sensor. It's very possible that the sensor is telling the computer that the car is warmer or colder than it really is and thus the fuel mixture is incorrect.

 

Have you plugged in a code scanner and checked for codes?

 

A high quality code scanner can tell you what temp the CTS is reporting. That can be very helpful.

 

GD

Nope, no idiot lights at all.

Okk, so i need to get the codes checked even with no lights on the dash being lit?

Nope, no idiot lights at all.

 

Does the check engine light come on when you first turn on the ignition (bulb check)? Just beacuse you don't see the light doesn't mean there aren't stored codes. It wouldn't be the first time I've seen a used car where the idiot light was bypassed or rewired to come on with one of the other idiot lights durring the bulb check and then go out when you start it....

 

GD

Sounds like an air leak. Check the intake tube clamps, make sure they're tight at both ends.

Check all of the breather hoses where they attache to the intake tube and the valve covers.

Check the hose for the idle control valve It's the large ~1" hose about 8-9" long that sticks out the side of the intake tube right behind the MAF sensor.

Speaking of MAF sensor, get a can of MAF sensor cleaner and shoot it a few times to clean the element.