92Legacy LS/FWD - engine sputter/misgfire when light load/cold or wet

[jvasquez8]

Ok,

 

Let me start by saying I am a auto-mechanic lightweight.

 

I recently inhereted an 92 Subaru Legacy L 2.2L. When the engine is first started (cold), it idles fine, but under light load the engine sputters, misfires. When I floor the accelerator, all the issues go away, but are there until the engine is warmed up. Once the engine is warm everything is OK. Also, when I drive in the rain, the problem rears its head, but not as bad as when it is cold.

 

I had the spark plugs/wires replaced. Put fuel injector cleaner in the tank over the last 3 tankfuls.

 

I took it to 3 different mechanics and they have told me several different things.

 

1) Need to replace injectors (2 are bad, but other mechanic disagrees)

2) Replace Cats, they aren't working well until they are warm.

3) MAF

 

I am relucatant to spend a lot of money on the car, since I own 2 relatively new cars. This car is a great city car, and I'd like to keep it if it's cheap to own.

 

Thanks for any advice.

[Legacy777]

First thing I suggest doing is checking the ECU for trouble codes. You can do this yourself via the instructions on my site.

 

Next......does the problem only happen immediately when you start the car, or is it still there after a minute or so of driving until things warm up?

 

I don't think any of the things the mechanics say are the issue. The catalytic converters usually don't go bad, and when they do, they get plugged up and you'll have decreased performance all the time, especially when warmed up.

 

The injectors.....if the injector was bad bad, it would throw a trouble code.

 

Other thing you might want to check/replace is the coolant temp sensor. it's a 20 dollar part that tells the computer how to adjust the air/fuel mixture of the engine. It would explain the poor running while cold....but not necessarily the issues when it rains.

[jvasquez8]

Thanks for the advice.

 

The problem only occurs when I start the car. It usually persists for about 10 minutes or so until the car is warm.

 

I agree that I don't trust the mechanics advice on these issues as well.

 

I'll post follow-up soon.

 

Thanks again.

[jvasquez8]

Is there a pointer somewhere on where the Coolant Temp Sensor is and how to replace it? Is this something that could be done by a relatively green DIY'er? (I used to work on old Yamaha bikes, but this is a different level of complexity).

 

Thanks in Advance.

[Legacy777]

It's a simple sensor connected to the coolant runner under the intake manifold. All you have to do is unscrew it.

 

here's a pic. It's the brown one

http://www.main.experiencetherave.com:8080/subaru/images/injectrs/DCP_2477.JPG

 

here's a better pic to orient yourself where the sensor is, in relation to the engine

http://www.main.experiencetherave.com:8080/subaru/images/injectors/DCP_2476.JPG

[Log1call]

Hi,

 

check the TPI is adjusted right too, when the throttle idle contacts are shut the ignition timing is set to an advanced setting which can cause missing and surging if the butterfly opens while the contacts are still shut.