I have two questions. My 91 Legacy has the "looping" idle problem. The engine will almost stall, then catch itself, then almost stall again, then catch itself again... you get the idea. It doesn't seem to matter if the car is in park, neutral or drive (it's an auto), or if the A/C is on or not. Oh yeah... it doesn't do this all the time, but it has been happening more frequently lately. I ran some injector cleaner through the tank a while back, but that didn't seem to help. I also checked the vacuum hoses, but couldn't detect a leak. The spark plug wires aren't new, but they seem OK and I can't detect any arching under the hood. Any ideas? I have a feeling this is a common problem, and a sensor is to blame.

 

Regarding the auto tranny (4EAT), it's having trouble engaging 1st gear (feels like it's low on fluid, but it isn't). I have a feeling the famous internal seals I've read so much about are going bad and will need to be replaced soon. I'm wondering if anyone has tried using an auto tranny additive in the 4EAT... will it buy me a little more time? The car is still quite driveable, so I certainly don't want to do anything that might make it worse!

 

Thanks!

 

Gavin

91 Legacy LS

82 Brat GL

Your problem with the up and down engine idling could be a problem with the Idle Air Control unit (IAC). You may need to replace it.

 

Here's the link to show you where it is and what it looks like:

http://www.main.experiencetherave.com:8080/subaru/images/injectors/DCP_2470.JPG

 

And the Canister Purge Solenoid Valve may also be involved in this case:

http://www.main.experiencetherave.com:8080/subaru/images/injectors/DCP_2471.JPG

 

Both items are easy to replace, assuming your hands are small enough to go in between (or under) the two intakes (for replacing the CPSV). Replacing the IAC involves clearing some tubes and valves (and probably the main intake hose, the big black one).

Both items are easy to replace, assuming your hands are small enough to go in between (or under) the two intakes (for replacing the CPSV). Replacing the IAC involves clearing some tubes and valves (and probably the main intake hose, the big black one).

Thanks! I'll focus on the IAC first.

Thanks! I'll focus on the IAC first.

Yeah, I had the same idle problem with my 91 turbo. If I was sitting at a stoplight for too long the revs would start bouncing up and down and after a month or two it would go so low it would stall sometimes. My IAC was plugged up with carbon and after my mechanic took it apart and cleaned it (a new one cost too much) it has been fine ever since.

 

As for the tranny, good luck. It seems that all of those auto 1st gen legacies need a rebuild at some point. Mine went at 180,000 kms.

Looks like I'll be pulling the IAC this week! Thanks for the advice.

 

Any thoughts on the tranny additives? Will they help, or could they possibly aggrevate the situation?

 

Gavin

Hey, I had the same problem for awhile and ended up changing my air filter...Solved the problem...May want to try checking it before you do anything else...easiest solution

Hey, I had the same problem for awhile and ended up changing my air filter...Solved the problem...May want to try checking it before you do anything else...easiest solution

Makes sense... I'll check that out first, although I believe the filter is less than a year old.

 

Thanks!

 

Gavin