Stuttering Problem - Everyone stumped...

[impreza_GC8]

Torque converter is a very good guess and from watching that vid it almost looks like someone who doesn't know how to drive a manual trans car is nearly killing it from a stop.
Also, from watching the vid, let me say that your car is in beautiful condition for its age. That paint is gorgeous. I wish I had your shell to drop my engine and drivetrain into.

[Stang70Fastback]

Torque converter is a very good guess and from watching that vid it almost looks like someone who doesn't know how to drive a manual trans car is nearly killing it from a stop.

Exactly, lol. I feel an idiot when I'm driving it. I wonder how much a torque converter/tranny in good nick would cost me. Off to the classifieds!

Also, from watching the vid, let me say that your car is in beautiful condition for its age. That paint is gorgeous. I wish I had your shell to drop my engine and drivetrain into.

You're not the first to say that. Once you get close you can see quite a few pretty bad issues, but it is true that where it isn't scuffed it does have a nice deep color and shine. I don't understand that either, because it's originally a NJ car and us usually covered in salt in the winder and out in the sun a lot in the summer. I guess I got a good one, lol.

[Plays_with_Toys]

Call me crazy, but I don't see how a torque converter can cause the car to limp like that when he says this:

Sometimes when I accelerate, when I first tap the throttle (again lightly - maybe it does it if I go WOT but it's so short it isn't noticeable) but when I lightly tap the throttle (say 5-10%) the engine will literally cut out for a second and the RPMs will drop and then it will rev up. This is NOT the same issue as above

Sounds like a fuel delivery/combustion issue. And contrary to what he says, it sounds like it is exactly the same problem as above.

Ok, since you have said a few things which point to not being very mechanically inclined lets cover the bases.

1. Spark plugs (NGK or Denso, nothing else, gapped correctly)
2. Plug Wires
3. Fuel Filter
4. Air Filter
5. PCV valve

These are the things that are replaced in a routine tune up. If these have not been replaced, then you certainly haven't taken the diagnosis, well... anywhere. You said that things were checked. I don't know how you can check a fuel filter, sniff it? And did they pull the plug wires and spark it against the frame to see if they were igniting or what? Not entirely sure how the mechanics "checked it" especially when you said you turned down the diagnosis service, which means you might have turned down them ever looking at the car. That wasn't very clear.

If it were the torque converter acting up, it is binding upon start up, which is causing the RPMs to drop down as the engine struggles to move. The other way the torque converter/transmission would act up is the engine would rev up with no real response. The reason is that transmission fluid is the working fluid in the system. The torque converter is used all the time in delivering power and uses transmission fluid to transfer torque through its centripetal force. I would think a torque converter issue would show itself through your gas mileage and in higher speeds. What is your gas mileage (city/hwy)?

That's like people jumping on the headgasket bandwagon everytime one of these things over heats. They jump in saying this must be the problem because they haven't gone through the steps to figure it out. $1000-2000 later their car overheats again because they never fixed the real problem in the first place.

[Stang70Fastback]

Alright, well you took the time to deliver a very thorough post, so I'll try to reply thoroughly

Call me crazy, but I don't see how a torque converter can cause the car to limp like that when he says this:

Sometimes when I accelerate, when I first tap the throttle (again lightly - maybe it does it if I go WOT but it's so short it isn't noticeable) but when I lightly tap the throttle (say 5-10%) the engine will literally cut out for a second and the RPMs will drop and then it will rev up. This is NOT the same issue as above

Sounds like a fuel delivery/combustion issue. And contrary to what he says, it sounds like it is exactly the same problem as above.

I see what you're saying, but first off, these are two different issues. The problem where the engine seems to cut out is completely independent of the stuttering issue (e.g. they can happen exclusively or both at the same time.) ALSO, you're saying it's the clutch bogging the engine down, but I forgot to mention the very important point that this will happen in park, or neutral. When it happens in gear it feels more like the engine cuts out than the car bogging it down (e.g. no movement.)

Ok, since you have said a few things which point to not being very mechanically inclined lets cover the bases.

1. Spark plugs (NGK or Denso, nothing else, gapped correctly)
2. Plug Wires
3. Fuel Filter
4. Air Filter
5. PCV valve

These are the things that are replaced in a routine tune up. If these have not been replaced, then you certainly haven't taken the diagnosis, well... anywhere. You said that things were checked. I don't know how you can check a fuel filter, sniff it? And did they pull the plug wires and spark it against the frame to see if they were igniting or what? Not entirely sure how the mechanics "checked it" especially when you said you turned down the diagnosis service, which means you might have turned down them ever looking at the car. That wasn't very clear.

I should have checked the post I copied. It does say that I turned down the diagnostic because they wanted to charge me for it, but what ended up happening was they took the car for the day free of charge to try and find the issue. Their best mechanic worked on it. Unfortunately, I do not know exactly what he looked at. I'm fairly certain that he checked the spark plugs because I remember talking about that but I'm not certain. The plugs were replaced not-too-long-ago I believe (at least when the head gaskets were done which was somewhere in the order of 40k ago.) I did replace the air filter a week ago to no avail. I wouldn't know anything about the plug wires, the fuel filter and the PCV valve. He might have checked all of these, he might not have, I don't really know.

If it were the torque converter acting up, it is binding upon start up, which is causing the RPMs to drop down as the engine struggles to move. The other way the torque converter/transmission would act up is the engine would rev up with no real response. The reason is that transmission fluid is the working fluid in the system. The torque converter is used all the time in delivering power and uses transmission fluid to transfer torque through its centripetal force. I would think a torque converter issue would show itself through your gas mileage and in higher speeds. What is your gas mileage (city/hwy)?

Yeah, I don't have any problems with the engine revving freely (I guess a slipping clutch issue is what you're talking about) and I get about 400 miles to a tank on drives to and from NJ, so gas mileage is perfect.

That's like people jumping on the headgasket bandwagon everytime one of these things over heats. They jump in saying this must be the problem because they haven't gone through the steps to figure it out. $1000-2000 later their car overheats again because they never fixed the real problem in the first place.

I know what you mean. Here's another tidbit that may or may not be relevant, I don't know. Another issue I have is when I come to a stop, I usually have to knock the car into neutral otherwise the whole car starts shuddering and it feels as if the car really wants to go forward, as if the clutch, or torque converter - whatever you want to call it - isn't disengaging all the way. When I knock it into neutral, the revs go up like by about 100 RPM and then settle back down. Maybe that's a sign the torque converter is acting up?

[SubaGlue]

I agree with others: Spark plugs / wires.

My Leggy had a misfire problem and it sputtered strangely like that. after i got new plugs and wires it ran fine

Thats my guess

[LegacyRob]

Try putting some of that transmission stop slip stuff in your tranny to see if that helps. If it makes a difference then maybe your on to something.

[Huffer]

Try putting some of that transmission stop slip stuff in your tranny to see if that helps. If it makes a difference then maybe your on to something.

Not a good idea. The only additive I would put in a 4EAT would be Lubegard ATF Protectant.

[99gtlimited]

for the bogging issue i'm thinking throttle position sensor

[Stang70Fastback]

I would absolutely love to have everyone here take turns and try their recommendations, lol. There are so many different opinions!

Someone else was telling me it might even be the cats...

[decke48]

doesnt its go hard into gear?
pluged cat will make the car bog down and sputter

[Brockley]

It seems you have a lot of people around you on here it may just take a trip to a junk yard and a case of beer and you could have the problem fixed.

Yeah. We'll have to see what's what here. This sounds like it really is the problem and if I can get people to help me out here since I don't know anything about this stuff, maybe I can rustle up some $$$.

Thanks for the help!

Yea man, Me and Mike can both come help sometime, we did the tranny on my GT, plus worked on swapping two WRX-RS's so its fairly easy at this point.

Did you check all the vac. lines running into the intake? I know when I had mine apart, it stuttered really bad, but I never drove it, so not sure if it would have gone away like yours.

Or better yet, lets just find me a Postal wagon now, and you can get the parts you need for cheap.. lol

Brock

[Stang70Fastback]

Just a new development. Sitting around outside waiting to pick up my friend (car warmed up and idling.) All of a sudden I started to hear the idle dropping a hair and then going back up again and then dropping again. I thought "ohhh no..." and sure enough it started getting worse until it was stuttering just like the problem I've been having with light throttle application. It got worse and worse over the next like 30 seconds to a minute to the point where I thought it would stall. It would drop down to ALMOST stalling and then shoot back up and then stall again. If you plotted the RPMs it would look like a sinusoidal curve getting bigger and bigger. And then, for the first time ever, it actually did stall. It wasn't violent. It just kind of died almost as if I'd turned it off. That's NEVER happened with this stuttering problem, but then again it's never done it idling either. So I started it up, it ran for 30 seconds, then did the same thing and stalled again. So before turning it on again, I booted up my carputer, plugged it in, started the car, connected the OBD-II and monitored the MAF sensor, intake manifold pressure, fuel loop status and one or two other things hoping to see something when it happened again, but of course the car ran like a top after that.

So I still dunno what's going on but it's obviously getting worse

And STILL no FREAKING CEL.

[Huffer]

I'm going to say carbon build up in the intake manifold/throttle body and an unclean Idle Air Control Valve. I have the same issue with my car, it's a manual though. But when idling, my car will idle like a race car. Up/down.

I just haven't made the time to clean the TB and the IACV.

[Stang70Fastback]

Today I stopped to fill my tires up with air, and left the car running while I did that. Got in, went to pull out of the Exxon station, as I went to turn the wheel to turn onto the road, I couldn't turn it and realized that for the second or two when i coasted into the street, the car had stalled. Had to LUG the wheel over, and pulled the car into a parking lot. This has gotten to the point now of being dangerous because the car is going to start stalling randomly whenever I'm off the gas. Started it up and it did it three more times, and then was fine again. This time I watched the MAF reading (which reads .5, .6, .4 depending on where it was in the RPM range) and not once did it fluctuate to something ridiculous, so I think the MAF is fine.

[Huffer]

Could be the neutral switch on the tranny then - if it's fritzing out it can send a signal to the tranny that it's in neutral...

Kinda clutching at straws here - but even if the MAF is registering the right voltage, it could be something else further down the line like a vac. leak.

[evolegacy]

other than his most recents posts, i have had the same issue, including a couple stalls but my issue was fixed when i changed my plugs, wires, and coil, but stupid me bought cheapos and now its acting up again, hehe.

I'd check the vac lines as well, i just checked mine tonight because of a CEL P0106 (MAP/MAF malfunction: dirty/defective [blame run from MA to CT ^_^"]), and they were pretty bad, going to just replace them all with this upcoming paycheck.

[Stang70Fastback]

Well, I'm going to be driving the car 45 minutes to a nearby place where a member of the Car Club here has offered to swap the whole intake manifold on the car and see if that helps. Hope he knows what he's doing, lol.

[Huffer]

Why swap an IM? You could just clean it!

[Stang70Fastback]

Yeah, decided against it. They guy's kind of shady. Instead, I'm driving 8 hours up to NJ next weekend (assuming the car makes it) and I'll stop off at his place on the way up and just pick up an MAF he has lying around and swap that out at home and see if it helps...

[evolegacy]

im grabbing decke's MAF this sunday, I'll post if it improves on my end.

[STL97outback]

My car is having the exact same issue as discussed on the beginning of this thread. Mine is a 5 speed manual, 118k mile outback, stock.

In 2 weeks I am doing the full fuel filter, spark plugs, wires, air filter, pvc valve stuff, and see if that cures it.

If not, then I will do the TPS sensor. Any one know how expensive or difficult the TPS is?

Thanks

[jey]

If not, then I will do the TPS sensor. Any one know how expensive or difficult the TPS is?

Not difficult, but you will need an OBD-II scanner so the TPS can be calibrated correctly. I've got one we can use if you decide to change it out...

[STL97outback]

If not, then I will do the TPS sensor. Any one know how expensive or difficult the TPS is?

Not difficult, but you will need an OBD-II scanner so the TPS can be calibrated correctly. I've got one we can use if you decide to change it out...

The TPS and PVC (these are the two I am not familiar with), do these need to be OEM or just parts store?

Can I install them with you this weekend?

I also sent you an email per your request

[legacygt420]

CHANGE YOUR PLUGS AND WIRES!!!

[STL97outback]

CHANGE YOUR PLUGS AND WIRES!!!

.....................

In 2 weeks I am doing the full fuel filter, spark plugs, wires, air filter, pvc valve stuff, and see if that cures it.

[Stang70Fastback]

Will be replacing the MAF Sensor this weekend.

Just an update on the most recent events of the past three days since I'm bored:

1. Waiting to pick someone up. Car hiccuped once (as in RPMs dropping then kicking back up) then seemed fine. Shut it off to avoid any more issues. When she got there a few minutes later, I started the car only to find the revs going all over (almost stalling then kicking up really high.) Rather than let it stall, I just decided to GO and gave her some gas. It was awful, lol. Car was hiccuping all the way up to 2500 RPM, lurching as it went, then after about 10 seconds of wild bucking the car was fine again.

2. Car was running fine then I went to give it some gas only to realize it stalled while I was coasting down the hill. I hadn't noticed because the air was on high and I was coasting in a straight line and when it stalls like that it's not violent at all, it just dies. This was right after I had been doing some doughnuts in a snowy lot so when all the dash lights came on I got really worried, but then saw the tach and realized it had died. Started it up while I was coasting at like 30 and it was fine. (Can anyone explain why the AT Temp light always flashes whenever you start the car after it stalls like that? Used to have that happen all the time when the head gasket was gone and the car would overhead and we had to turn it off while moving occasionally.)

3. Started the car after class. It had been sitting in the lot (20 degree weather) for about 90 minutes after being driven TO class (it was almost warmed up when I got there to begin with.) Started her up and the RPMs immediately started fluctuating between 800 and 1300 RPM. Watched as it got worse till it ALLLLMOST stalled, but then kicked up and jumped up to 2000, then slowly came down and kept going till it almost stalled but then kicked up to 2500 where it stayed for like 5 seconds before slowly coming down. Then it was fine.

I am AMAZED that through all of this nuttiness the CEL never comes on, lol.

[decke48]

so you did the tune up? sound like a lean fuel condition or plug exhaust to me.

[evolegacy]

a few comments in this topic is starting to make me wonder about my torque converter, i have that issue with getting little to no power for x amount of time in 1st gear. as for the RPMs dropping when it first starts to move, it only does it when the car is cold/just started up, could be normal or signs of possible issues later? idk.

other than that, i just need to do a 'good' tune-up and not this cheesy one my cousin helped me do from advance auto parts last year (2 of my plugs are fouled :-/).

[jey]

CHANGE YOUR PLUGS AND WIRES!!!

Yeah the TPS aint cheap, we'll be better off doing the plugs, wires, and air/fuel filters first since they're maintenance items.

[Stang70Fastback]

Interesting event a half hour ago:

I've noticed that one of the causes of this problem seems to be after I've driven the car somewhere, let it sit for a little while, then when I go start it again, THAT'S when it will immediately have problems. Drove the car to Wendys, spent 10-15 minutes inside picking up food, went outside. Started car, backed out of parking spot, drove forward, as I'm turning around passing the drive through lane the car want's to go straight. At first I thought it was ice jammed in the wheels (there's a lot of it, lol) but then realized it stalled. Started it again, finished the turn and it stalled again... fuck. Went to start it a THIRD time but THIS TIME nothing happened. Lights come on on the dash and that's it. NOTHING else, no ticking no noise nothing. FUCK FUCK. Tried a few more times to no avail. So I let it sit for a bit. In hindsight I MIGHT have been dumb enough to have it in drive, but I'm fairly confident it was in neutral/park for these attempts. After sitting it started... stuttered... stalled. Started it a fourth time, and it seemed to run ok. Drove it all the way home and whenever I was coasting or braking I was doing so with my left foot with the right foot revving the engine with the tranny in neutral.

Fun times. Looking forward to the 450 mile drive home this Friday for spring break, lol.