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fjs1229
12-30-2009, 09:04 PM
Hi guys
I posted this on another forum (not a car specific one) and the first reply I got was: "My only advice that I can give ya is that you can check out www.dirtyimpreza.com (http://www.dirtyimpreza.com/forums/../)
Most of these guys have a doctorate on their Subies so im pretty confident that they can help ya"
so here I am.

Anyway:
I'm not really a "car guy" so im going to give you as much info as I can so maybe you can help.
my girlfriend has been having a bit of trouble with her car lately, it's been to a couple different mechanics but the problem isn't fixed. Of course, other things got fixed, but the original issue is still there. FYI the car is a 1997 Subaru Impreza L Wagon AWD F4-2.2L

The car recently had a new clutch installed. Before the first clutch went it had no power up hills, and right before it went the car started doing this thing where it would stutter and buck like it was running out of gas when it had plenty. So she's on the highway, it starts bucking and the clutch pedal drops to the floor. It got fixed. Its an adjustable clutch and the mechanic says it'll need to be adjusted after about 1000 miles. This mechanic is up at our school in Vermont.

The car runs great for a while but sure enough it starts doing that bucking thing again. It's really intermittent, and we can't really pin down when and why it happens, but heres what we've got: It starts when you take your foot off the gas. Not everytime you take your foot off it, but seemingly randomly. Now, that's the stutter. Sometimes when you get back on the gas it'll start actually bucking. Sometimes it isn't too bad, sometimes it's pretty violent. It also seems to be worse on hills, although it's happened on flat roads as well. It's not connected to a specific gear, but sometimes only one gear is tempermantal. On the highway the other day it was doing it in 5th and 4th. The lower gears were fine. Another time it was doing it in 2nd but 3rd was smooth. Once it would NOT stop bucking in 3rd, but drove ok in 2nd.

It drove home to Mass without much problem, a little temperamental but no serious bucking. We brought it to my family's mechanic and said the clutch needed to be adjusted, since it was around 1k miles since it was added. Since the bucking happened right before the clutch went we figured it was related. He drives it and of course has no problems with it, then we talk to him and tell him about the bucking, how it usually starts on hills, etc. He takes it out again and goes up some hills and says everything is fine. Didn't touch a thing (and didn't charge us for his wasted time, thankfully).

We drive it to her house in southern mass. We're near her house when it starts bucking really hard in 5th and 4th. We get right off the highway and it's bucking in 3rd and a little in 2nd. We pull into a parking lot and sit for a while thinking about what to do. We drive it in 1st and 2nd through the parking lot after a while and it's fine, so we go home and it has no issues in 3rd gear (we went through town instead of on the highway, just incase)

We bring it to her mechanic at home. He loosens the wire (or whatever it is) on the clutch a little and does a bunch of front end work (struts, other stuff. Honestly im not really sure, her dad didn't tell us everything that was wrong, but apparently it was "a lot of stuff")

Anyway, the ****ing thing still bucks and we're both really worried about it. The bucking is so violent it seems like it could definitely be doing some damage. We're at my house and we still have to go back down to her house and then back up to vermont for school and really dont want to be broken down on the side of the highway.

Im looking at a "demo" list of TSBs for the car, but I cant access the full bulletin without registering at the site. I was wondering if anyone has access to them and could help out.
These ones caught my eye:
166297 MAY 97 Transfer Clutch - Binding And/Or Bucking On Turns (Im not sure if it happens specifically when the car is turning, but it might?)
TT0101-001 JAN 01 Engine - Oil Pump Replacement vs. Resealing (really not sure)

Does anyone have any other insight? Maybe other parameters to look at next time (and there WILL BE a next time) it starts doing it to get a better idea?

bone_1113
12-30-2009, 09:16 PM
I had something similar happening to me on my 91 sentra...and it turned out to be the PCV...lol...sounds almost exactly the same...stuttering and bucking at random times when letting off or getting on the gas...not sure if its the same for you but heck check it out anyways!

p.s. I just replaced the PCV on my 98 Impreza L wagon and it was stuck open (doesnt really hurt the cars performance as much as if it was stuck closed) and packed with carbon.

tony

Doncolberto530
12-30-2009, 09:44 PM
Is the stuttering most apparent when slowing down? Like say coming to a stop and shifting down? My WRX is doing the same thing and I have yet to figure out what the problem is. I replaced the clutch and went to get my timing belt replaced only to have the stealership tell me I need a new clutch... Fun stuff:machinegunleft: I have been having the clutch stick to the floor on occasion also so am wondering if it all could be connected some how. Subscribing now...

MilesFox
12-30-2009, 10:14 PM
try posting on www.ultimatesubaru.org/forum for the best collective knowledge and folks familiar with Legacy.

There are a lot of USMB members around here to help you out. Its a small world with subaru enthusiasts. Everyone is everywhere.

wagonryan
12-30-2009, 10:52 PM
hmmm I don't think we have the same problem but my car bucks when i floor it or when I'm in too high of a gear for the speed. someone pointed me to a thread on rs25.com about a grounding mod, which has helped a lot of people with bucking but i have yet to do it myself.

i'll try to find it

Gnome
12-31-2009, 09:38 AM
this may sound dumb and i i will probably get alot of **** for it. but my Ex-gf's honda did something like this. she had a squirel ( yes im not kidding a squirel) living in her car. anyways it got sucked into the intake somehow and caused all sorts of meyham anyways bottom of the story maybe its your air intake, not getting enough or getting too much could do what your saying in my opinion... who ever posted with the WRX do you have an aftermarket air intake?
If i get totally blasted for this post i understand lol....
GNOME:FU:

fjs1229
01-01-2010, 08:18 PM
Well, tonight it broke down in boston and had to be towed. We stopped at a light and when it went into first it bucked REAL hard and stalled. Then it would turn over but it didn't sound right. Pushing on the gas did nothing. The idle was really rough. The engine sounded... muffled... more quiet than usual and kinda muddy sounding. We tried for about 15 minutes to get it started up again but it wouldnt go. Then we got towed about 40 minutes away. The car turned over fine in the parking lot of the garage and we were able to put it in reverse and 1st to park it, but we didn't bother driving it home. ....

jakeachy
01-01-2010, 09:54 PM
bucking as you describe it is telltale severe ignition retarding. Your AFRs,timing values, maf readings, 02 readings(faulty sensors), or knock sensors are reporting something either serious or faulty to the ecu. The ecu is saving itself from real detonation by pulling all timing, basically shutting down the motor per se.

check your maf and 02s.

Doncolberto530
01-02-2010, 12:27 AM
this may sound dumb and i i will probably get alot of **** for it. but my Ex-gf's honda did something like this. she had a squirel ( yes im not kidding a squirel) living in her car. anyways it got sucked into the intake somehow and caused all sorts of meyham anyways bottom of the story maybe its your air intake, not getting enough or getting too much could do what your saying in my opinion... who ever posted with the WRX do you have an aftermarket air intake?
If i get totally blasted for this post i understand lol....
GNOME:FU:


Yeah, I have an AEM Short Ram intake.

punkrockerjohn
01-02-2010, 12:41 AM
bucking as you describe it is telltale severe ignition retarding. Your AFRs,timing values, maf readings, 02 readings(faulty sensors), or knock sensors are reporting something either serious or faulty to the ecu. The ecu is saving itself from real detonation by pulling all timing, basically shutting down the motor per se.

check your maf and 02s.


Those would all give him a check engine light wouldn't they ?

shatteringstar
01-02-2010, 01:15 AM
my only dumb advice: could the pitch stop be broken? that would cause the engine to buck ALOT.

its easy to check atleast.

97ScoobyL
01-02-2010, 05:25 AM
Those would all give him a check engine light wouldn't they ?

not exactly.

I agree with jakeachy that this deffinatly sounds like a sensor issue. Also its not good to jump from one shop to another all the time when chasing a constant problem. You will get more wrong diagnosis that way because of not knowing what the previous shop/technician exactly did to the car. if you havent already i would take this issue to the subaru dealership and have it diagnosed there. They will have the best equipment and knowledge to help you.