96 legacy very rough idol when stopped in drive.

[tedbull]

We purchased a 96 legacy L a week ago with 81,000 miles from the elderly original owners and all services up to date. The wagon starts up just fine and idles great and purrs in park or nuetral. But in reverse and very noticeably in drive at a stop light it idles very rough. It usually idles smooth at 700rpm but when idleing in drive it drops to around 500 and shakes fairly violently. Definantly not normal. I feels like it is in the automatic transmission, Maybee torque converter? Anyone have input on this. Also where is a good resource online for a subaru tourqe converter? I spent a couple hours searching this topic and looking for parts. No luck.

[johnceggleston]

We purchased a 96 legacy L a week ago with 81,000 miles from the elderly original owners and all services up to date. The wagon starts up just fine and idles great and purrs in park or nuetral. But in reverse and very noticeably in drive at a stop light it idles very rough. It usually idles smooth at 700rpm but when idleing in drive it drops to around 500 and shakes fairly violently. Definantly not normal. I feels like it is in the automatic transmission, Maybee torque converter? Anyone have input on this. Also where is a good resource online for a subaru tourqe converter? I spent a couple hours searching this topic and looking for parts. No luck.

 

this is not an uncommon problem. those who know more than i do seem to think it is associated with crappy aftermarket axles, they transmit the engine vibration to the rest of the car. it seems odd to me but when the axle/s were replaced and the problem solved it is hard to argue against.

 

but some one else will know more.

 

did it do this before you bought it?

have you had an axle replaced?

any recent service?

 

a fluid change wouldn't hurt, check at 30k replace at 60k. but if you want your trans to outlast the car replace it every 30k. you can do it your self, drain the trans pan, and fill with the same amount, about 3.5QTs. drive a bit and repeat. the trans hols about 9+ qts.

 

i doubt you need a torque converter, or a trans for that matter. i have never read of a subaru TC going bad.

 

used parts online

 

http://www.car-part.com

[OB99W]

While it's not impossible for there to be a transmission problem that excessively loads the engine, it's not common.

 

Unlike years ago with uncontrolled carburetors, the engine management system on modern cars compensates for loading, so the drop in idle speed from 700 rpm (I assume that's when in neutral) to 500 rpm in drive isn't normal.

 

When idling in drive, if you take your foot off the brake, does the car creep forward, does the idle smooth out, and what rpm do you see?

[idosubaru]

doubtful a transmission issue and less likely torque converter.

 

probably engine related, not transmission. it's just noticeable when you put a load on it (in gear). very common for that to happen.

 

age and miles on the plugs and wires?

are the wires Subaru or something else?

 

any check engine lights in the past year or so?

[Rooster2]

I am thinking that new spark plugs and wires are needed for your car. Though number of miles is low, I bet the plugs and wires are the originals and need replacing.

 

I would also suggest that you add some fuel injector cleaner to the gas tank. Get the good stuff that costs about $6/bottle, like Chevron Techron or TLC. The cheap stuff for $3 or $4/bottle doesn't help much in my opinion.

[tedbull]

I have only had the car for a week. I added seafoam to the fuel tank because the car was owned by a elderly couple who did not drive it much. The axles have never been replaced. The car had all of its serviced done on scheduale and at the dealer. The knock sensor and crankshaft sensors where replaced at some point because of a check engine light. I plan on doing a full tune up.

 

Oil + filter

trans oil

rear diff oil

plugs and wires

cap and rotor

fuel filter

air filter

throttle body and idle speed valve cleaning.

 

I was given a tourqe converter by a friend today. It is out of a 92 legacy wagon. At least I have a spare if I need it. I will do the tune up this weekend and udpdate.

[OB99W]

plugs and wires

The EJ engines are fussy. Be sure to use original spark plugs and OEM Subaru wires.

 

 

cap and rotor

You won't be needing those.

 

 

EDIT: Also, check/clean or replace the PCV valve.

Edited October 6, 2010 by OB99W

[outback_97]

The wagon starts up just fine and idles great and purrs in park or nuetral. But in reverse and very noticeably in drive at a stop light it idles very rough. It usually idles smooth at 700rpm but when idleing in drive it drops to around 500 and shakes fairly violently.

 

FWIW my '97 OB does something similar. Sitting in "D" at a stop light, it will vibrate and shake quite a bit... shift into "N" and it goes away. Shift back into "D" and it will shake again, but not as bad. Sometimes it shakes badly enough that the front window will rattle if it's not cranked fully up or down. Other than this, the cars idles and runs just fine.

 

I have not had axles replaced. Mine has >160K miles and it has done this for years. I have heard this problem described on forums other times over the years and just have resigned myself to it being one of those Subie quirks.