Hiyas all!

 

I just picked up my first Subaru yesterday. I've quite a few cars, but had some questions about this one.

 

It's 1993 Loyale wagon, with 4wd and 197k. The engine was replaced at 150k.

 

I'm concerned that the engine seems to run rough, although from outside the car, it sounds super smooth. I understand that the flat four will run rougher than most inline 4's, and so I'm not really sure how to guage this. It stumbles under load at about 3000 rpm. I'm inclined to think that it needs new plugs/wires/distributor cap, etc. and will likely be doing that this afternoon.

 

This morning, as I was driving it to work, the check engine light came on. I had been doing about 65mph for 10 minutes at that time. I'm wondering if it might be a bad catalytic converter. Is there an easy way to test this (without a code reader)?

 

My second question about the car involves the 4wd system. I understand that with the manual gearbox comes a locking center differential, meaning that it's not OK to drive it in 4wd on pavement. Is that correct?

 

Thanks a bunch in advance for any advice you might be able to offer. So far, I'm really enjoying the car.

The SPFI system is not capable of reading for a bad catalytic converter. You will need to pull the codes to find out what the CEL is telling you. There are no code readers for these engines - you have to plug in the white read memory connectors to get the codes.

 

Sounds like it could be an O2 sensor. But could be other things as well.

 

4WD is just like a truck. There is NO center differential - lockable or otherwise. When the car is in 4WD power is transfered to the front and to the rear diffs. There is no ability to compensate for turns thus it will bind like any other 4WD.

 

GD

 

It stumbles under load at about 3000 rpm.

 

Possibly a vacuum leak from one or more hoses. My advice: replace all the vacuum hoses/lines, secure their fittings and then if it still has the problem start diagnosing other things. Easy place to start & v-hoses are fairly cheap to replace and should be done every so many years anyway as maintenance. Do them all at the same time so you start out with them all the same age.

^^^^^^May also wanna check the timing.

Thanks a bunch!

 

I've replaced the O2 sensor, dist cap, rotor, plugs and wires and it runs SOOOO much better and the CEL hasn't come back on.

 

There's still some hesitation under heavy throttle below 2000 rpm. Could that be timiing, or vacuum, or something else all together?

First thing you need to understand is these cars are NOT powerhouses - lowend power is not something you are going to get out of them.

 

next - "power band" (and i use the term loosly here) on this car is around 3000-3500 rpms - below that, not much happening. they like the higher rpms.

 

is this a manual, or auto tranny? the 3spd autos are notoriously sluggish at low rpms.

 

and lastly - find out what that check engine light was about - seriously.

there are directions to read the stored codes posted somewhere here - a quick search should turn them up.

There's still some hesitation under heavy throttle below 2000 rpm. Could that be timiing, or vacuum, or something else all together?

 

Could be a dirty MAF sensor too. Sometimes that can cause some hesitation off the line (or at least cleaning it helped mine...)

Thanks for the help!

 

I'll get the codes pulled and clean the MAF.

 

Let me clarify a bit: below 2000 rpm it almost feels as though it's not firing on all 4 cylinders, about 2k, everything's great. It's even worse (surprise), and difficult to drive sedately, with the AC running.