34 replies to this topic

[WoodsWagon]

1998 Outback 2.5l. When stoped at a light, or anywhere, it vibrates ilding in drive. Put it in neutral, the noise goes away.

This seems like a common problem. The solutions have ranged from PCV valves to Juju majic, and front halfshafts.

I would like a list of
A) How many have this problem and
What solution if any, you have tried (other than throwing it in neutral or ignoring it.)

[JPX]

What solution if any, you have tried (other than throwing it in neutral or ignoring it.)

Neutral when I care - 1996 Legacy 2.2L sedan.

[jon38iowa]

I don't know if your car has one, but mine has a MAF sensor. My car had a rough idle despite a total rebuild! Cleaning this made all the difference and no more rough idle.
Look it up here on search, much info available.

[backwoodsboy]

Ive got a '93 leagacy with the 2.2.....and the same problem.

Somebody on here was saying the other day that replacing the gasket where the oil fill tube meets the block is the key.

It makes sense to me......changing that gasket would stop the vacuum leak, and kick the idle up enough to stop the vibration.

Im gonna try it for myself, and let yall know!

[Bmm001]

My '95 does it too. I just ignore it. The engine idles very smoothly, its the halfshafts. Seems to do it worse when warming up or with the A/C on. If it really bothers me, I just slip it in neutral, then put it back in drive.

Brian M.

[subeman90]

99 legacy here that does it. I go with the N trick too.

[nipper]

1998 Outback 2.5l. When stoped at a light, or anywhere, it vibrates ilding in drive. Put it in neutral, the noise goes away.

This seems like a common problem. The solutions have ranged from PCV valves to Juju majic, and front halfshafts.

I would like a list of
A) How many have this problem and
What solution if any, you have tried (other than throwing it in neutral or ignoring it.)

How many miles are on this car ?When was the last time the car had a tune up. Just for the hell of it check the crankase pully to make sure it isnt loose. Is there any time that its worse or better? nipper

[ericem]

I just slide it in neutral as well, some days, i can NOT feel the car idle, other days, you can feel it hard, but doesn't the torque converter have something to do with this? Does it dis, engadge or something when i stop? but then again, some days i can feel it idle in Park:-\ So maybe i should clean my MAF, with some Q-tips.

[Manarius]

Unless your car is bucking or acting really weird, don't bother messing with the MAF. The vibration you describe has been present in every Subaru I've driven - it's just a thing with the AWD system; a quirk if you will.

[mjreilly]

My 95 OBW does the same thing in drive, smooths out in N. I'm confused about how it could have anything to do with the drive train. If they car is stopped, in D or N, no part of the drive train is moving, correct? I've always chalked the vibration stopped in drive to a slightly low idle. If you put the car in N(or P) for that matter, the idle goes up a few hundred RPM and smoothes out.

I've replaced the plugs and wires and it helped a little. The Haynes manual mentions cleaning the throttle body, it can get gummed up and cause a low idle. I haven't done that yet. I've been trying to track down the CRC MAF cleaner but no one seems to carry it locally, next time my wife orders from Amazon I'm going to have her pick me up a can of it.

I'll report back if that helps.

cheers,

matt

[Manarius]

Consider how the car is working when it's in drive - the engine is still turning but you are holding the brake so the transmission still wants to move, but can't because you're holding on the brake. I believe the vibration you're all describing is a product of that.

[nipper]

I dont have that vibration. Subarus arent supposed to vibrate like that, most cars dont.
On the other hand its not something that is going to hurt the car.
Does it go away with the a/c on or get worse?

nipper

[nipper]

My 95 OBW does the same thing in drive, smooths out in N. I'm confused about how it could have anything to do with the drive train. If they car is stopped, in D or N, no part of the drive train is moving, correct? I've always chalked the vibration stopped in drive to a slightly low idle. If you put the car in N(or P) for that matter, the idle goes up a few hundred RPM and smoothes out.

I've replaced the plugs and wires and it helped a little. The Haynes manual mentions cleaning the throttle body, it can get gummed up and cause a low idle. I haven't done that yet. I've been trying to track down the CRC MAF cleaner but no one seems to carry it locally, next time my wife orders from Amazon I'm going to have her pick me up a can of it.

I'll report back if that helps.

cheers,

matt

there is a load on the drive train (which the engine is part of). When the car is in park or neutral, the engien is not fighting stopped driveline parts, since they are not engaged. When stopped in D or R, the engine is loaded by the stoped car.

nipper

[mjreilly]

I dont have that vibration. Subarus arent supposed to vibrate like that, most cars dont.
On the other hand its not something that is going to hurt the car.
Does it go away with the a/c on or get worse?

nipper

Mine does lessen when the a/c is on and the RPMs also increase slightly when the a/c is on. Does the ECU do this to compensate for the a/c at idle?

[OB99W]

Consider how the car is working when it's in drive - the engine is still turning but you are holding the brake so the transmission still wants to move, but can't because you're holding on the brake. I believe the vibration you're all describing is a product of that.

Perhaps, but perhaps not; a properly functioning trans torque converter shouldn't cause that to happen. My '99 OB has what I'd describe as a slightly rough/low idle (once the engine has warmed) when in drive and with my foot on the brake pedal. However, if I pull up on the emergency-parking brake and remove my foot from the service brake pedal, the idle improves substantially. In my case at least, I attribute the difference to two possible factors. One is that there may be a slight vacuum leak in the brake booster, and the other is that the brake lamps put an additional load on the electrical system that the alternator (and hence the engine) has to make up for. The "problem" isn't so bad that I've been motivated to determine the exact cause .

[nipper]

Perhaps, but perhaps not; a properly functioning trans torque converter shouldn't cause that to happen. My '99 OB has what I'd describe as a slightly rough/low idle (once the engine has warmed) when in drive and with my foot on the brake pedal. However, if I pull up on the emergency-parking brake and remove my foot from the service brake pedal, the idle improves substantially. In my case at least, I attribute the difference to two possible factors. One is that there may be a slight vacuum leak in the brake booster, and the other is that the brake lamps put an additional load on the electrical system that the alternator (and hence the engine) has to make up for. The "problem" isn't so bad that I've been motivated to determine the exact cause .

AHA! Thats a HUGE hint. When you put the parking brake on, you are no longer using the power brake booster. So now we suspect a ppinhole leak someplace in the power brake booster circuit. The booster uses engine vaccume to operate. Ok here is the next test. Unplug the booster and plug the line. Put the car in gear and with your foot on the brake does it still vibrate? If not you found the problem.

nipper

[nipper]

Mine does lessen when the a/c is on and the RPMs also increase slightly when the a/c is on. Does the ECU do this to compensate for the a/c at idle?

The compter adjusts the IAC motor to compensate for the additional load.

nipper

[OB99W]

[...]Ok here is the next test. Unplug the booster and plug the line. Put the car in gear and with your foot on the brake does it still vibrate? If not you found the problem.

Or, it could be determined less directly by logical process of elimination; disconnect the brake light switch and see what happens. If it's still rough (in the situation I described above), the likely culprit is determined (if not due to alternator load then vacuum leak). Maybe even unplug both the booster and the brake light switch (one at a time), since each could be contributing. Too bad I'd rather sit here and type than actually work on the car.

[nipper]

Or, it could be determined less directly by logical process of elimination; disconnect the brake light switch and see what happens. If it's still rough (in the situation I described above), the likely culprit is determined (if not due to alternator load then vacuum leak). Maybe even unplug both the booster and the brake light switch, since maybe the cause is a combination of both. Too bad I'd rather sit here and type than actually work on the car.

You could be leaking electrons, causing the vibration.

nipper

[OB99W]

(Darn, Nipper, you respond faster than I edit. )

You could be leaking electrons, causing the vibration.

Is that what those plastic outlet covers are for?

[Manarius]

I didn't think about the brake booster idea, but that's a rather understandable explanation. Either way, I just flip into neutral when I'm stopped for longer than a second or two and have no problems.

[Aspen]

My 99GT does this too for a long time now. I would love to cure it. I swapped the IAC unit out, cleaned the throttle body and flushed the trans fluid. It improved but is still there.

It's worse when cold or when the A/C in on.
Sometimes when it is nice and warm, it is non-existant.

If it's the brake booster then why would it be affected by the temperature?

I have also heard that the O2 sensor may be causing it.

A new MAF is way too much money to chance it. I think I will give the oil tube gasket a try and maybe the brake vacuum a try too.

[Manarius]

The MAF problem is very very noticeable. I would hardly call a slight vibration a MAF problem.

I also doubt the O2 sensor being the cause of poor idle either.

[OB99W]

My 99GT does this too for a long time now. I would love to cure it. I swapped the IAC unit out, cleaned the throttle body and flushed the trans fluid. It improved but is still there.

It's worse when cold or when the A/C in on.
Sometimes when it is nice and warm, it is non-existant.[...]

You might want to consider this: http://endwrench.com/images/pdfs/LegacyIdleSum04.pdf

[dj3stripes]

my 95 also has this 'feature' except i notice that when i experience the shakes, i slip it into neutral, and after about 2 seconds i slip back into drive. if i release the brake in the slightest and let it roll just a hair and re-brake the shakes happen again. i figured it was something to do with the car not knowing to let out of gear, or whatever, when the brakes were applied. my brakes squeal sometimes as well, but the pads are fine............. as far as cleaning the throttle, how would i go about doing that? does it need to be removed or can i simply spray a cleaner of some sort onto it (you're speaking of the 2 little pulleys that have the wires that pull back and rev the engine right, 2 because i have cruise ?)