wondercow2 Posted May 22, 2006 Share Posted May 22, 2006 Or bad driver... my 98 Legacy L is the first manual car I've owned, and I've put about 3000 miles on it in the 5 months I've owned it. I've noticed that when going downhill, or even on some flat ground, the car will lurch back and forward- as if it's engine braking and slowing down, and then suddenly deciding to accellerate, even though I'm holding the accellerator steady. This mostly happens in 5th gear, although I get all sorts of interesting shudders in 3rd when doing similar not-quite-coasting type things. If I let the car speed up the whole way down it's perfectly smooth, and braking the whole way seems equally acceptable although the braking may be dampening any shuddering that is happening. So is this normal, sign of a bad driver (should I be letting the clutch slip or something?), or a sign of a weary clutch? The clutch is original and the car has 130k on it. It passes all the clutch-wear tests (kills the engine goes uphill in 5th, though the RPMs do sometimes go up 50-200 from where they should be for a given speed on bigger hills). Quote Link to comment Share on other sites More sharing options...
brice k Posted May 22, 2006 Share Posted May 22, 2006 Im no Subaru expert. Just got my first one a few month ago, but it sounds like you need new engine mounts Quote Link to comment Share on other sites More sharing options...
wondercow2 Posted May 22, 2006 Author Share Posted May 22, 2006 Im no Subaru expert. Just got my first one a few month ago, but it sounds like you need new engine mounts Hmm, hadn't thought about mounts, mostly because the car is so smooth at idle (my last car, a 2.8l beretta, would shake like mad at stoplights from a crappy idle + bad motor mounts). Quote Link to comment Share on other sites More sharing options...
dmanaenk Posted May 22, 2006 Share Posted May 22, 2006 Possibly a dumb question, but is your AC on when you experience this? Quote Link to comment Share on other sites More sharing options...
nipper Posted May 22, 2006 Share Posted May 22, 2006 Or bad driver... my 98 Legacy L is the first manual car I've owned, and I've put about 3000 miles on it in the 5 months I've owned it. I've noticed that when going downhill, or even on some flat ground, the car will lurch back and forward- as if it's engine braking and slowing down, and then suddenly deciding to accellerate, even though I'm holding the accellerator steady. This mostly happens in 5th gear, although I get all sorts of interesting shudders in 3rd when doing similar not-quite-coasting type things. If I let the car speed up the whole way down it's perfectly smooth, and braking the whole way seems equally acceptable although the braking may be dampening any shuddering that is happening. So is this normal, sign of a bad driver (should I be letting the clutch slip or something?), or a sign of a weary clutch? The clutch is original and the car has 130k on it. It passes all the clutch-wear tests (kills the engine goes uphill in 5th, though the RPMs do sometimes go up 50-200 from where they should be for a given speed on bigger hills). Next time it happens downshift and see if it still does it. What speed and engine rpm does it. when was the last time this thing had a tune up, fuel filter plugs wires etc, it could be a coil issiue, coiuld be fuel delivery. Also have the codes pulled off the car and see what it is saying. nipper Quote Link to comment Share on other sites More sharing options...
keltik Posted May 22, 2006 Share Posted May 22, 2006 I have the exact same problem. I've found when engine braking down long hills, sometimes the rpm will fluctuate +-300rpm (Auto trans) at a rather rapid rate - maybe twice per second. I know for a fact its the IAC doing something weird (can hear the change in exhaust note out the window) i just cant figure out why....Stupid Honda. Is it possible your problem is being caused by the same thing? KELTIK Quote Link to comment Share on other sites More sharing options...
wondercow2 Posted May 22, 2006 Author Share Posted May 22, 2006 I have the exact same problem. I've found when engine braking down long hills, sometimes the rpm will fluctuate +-300rpm (Auto trans) at a rather rapid rate - maybe twice per second. I know for a fact its the IAC doing something weird (can hear the change in exhaust note out the window) i just cant figure out why....Stupid Honda. Is it possible your problem is being caused by the same thing? KELTIK My RPMs stay pretty constant. The problem was happening before I did maintenence, but I just seafoamed the car and changed the plugs (which looked fine anyway). The wires are still pretty new, there are no codes. The fuel filter is probably a bit old, but this is not a fuel problem, trust me- it ONLY happens when the car is in that twilight zone between engine braking and normal cruising. And no, the AC is off. I'd try downshifting, but, uh, I really don't think 4th gear was made for going 75mph downhill... Quote Link to comment Share on other sites More sharing options...
nipper Posted May 22, 2006 Share Posted May 22, 2006 My RPMs stay pretty constant. The problem was happening before I did maintenence, but I just seafoamed the car and changed the plugs (which looked fine anyway). The wires are still pretty new, there are no codes. The fuel filter is probably a bit old, but this is not a fuel problem, trust me- it ONLY happens when the car is in that twilight zone between engine braking and normal cruising. And no, the AC is off. I'd try downshifting, but, uh, I really don't think 4th gear was made for going 75mph downhill... You can downshift to third and not hurt anything, i mean, thats the "oh s**t i have no brakes" manuver. if you can run the car up to 75 in a gear, you can downshift it to that gear too. Now that said, your just being annoying now . The only thing i can think of is the IAC motor doing odd things. May be the only way to find out is to rent a scanner and drive it down hill and read the scanner. nipper Quote Link to comment Share on other sites More sharing options...
rlsimpso Posted May 22, 2006 Share Posted May 22, 2006 Just my 2 cents: The lurching problem you describe sounds similar to what mine did when the knock sensor want bad. I would buck and kick under acceleration. A/C made it worse, but then any time the compressor is running (defrost) the car gets a bit twitchy on the throttle. Mine threw a knock sensor code though. Replaced it and the problem is fixed. The L of that year is a 2.2, right? Fifth gear on a (up I am guessing) hill in a Subaru, are you crazy? Try a change or two down and see what happens. If the car starts shaking and making bad sounds, you most likely hit the rev limiter. Go up one gear if this happens. Try double clutching on the downchange if you are worried about grinding. I am guessing you may not know how to do that, as this is your first properly transmitted car. Check this link for information: http://en.wikipedia.org/wiki/Double_clutch Fourth is good to a bit over 100mph in the 98 GT. I am guessing it should be close in the 2.2. Quote Link to comment Share on other sites More sharing options...
nipper Posted May 23, 2006 Share Posted May 23, 2006 Just my 2 cents: The lurching problem you describe sounds similar to what mine did when the knock sensor want bad. I would buck and kick under acceleration. A/C made it worse, but then any time the compressor is running (defrost) the car gets a bit twitchy on the throttle. Mine threw a knock sensor code though. Replaced it and the problem is fixed. The L of that year is a 2.2, right? Fifth gear on a (up I am guessing) hill in a Subaru, are you crazy? Try a change or two down and see what happens. If the car starts shaking and making bad sounds, you most likely hit the rev limiter. Go up one gear if this happens. Try double clutching on the downchange if you are worried about grinding. I am guessing you may not know how to do that, as this is your first properly transmitted car. Check this link for information: http://en.wikipedia.org/wiki/Double_clutch Fourth is good to a bit over 100mph in the 98 GT. I am guessing it should be close in the 2.2. He said down hill or level ground, thought the knock sensor may be worth a peek. Usually the knock sensor is good about throwing a code. :burnout: :burnout: nipper Quote Link to comment Share on other sites More sharing options...
wondercow2 Posted May 23, 2006 Author Share Posted May 23, 2006 Uh, ok, I know you guys mean well, but I'm not a mechanical idiot here- the motor is nowhere redline or the rev limiter, there are no codes, and the problem is NOT related to acceleration in general-as I've said several times now. It happens when going downhill or gently downhill, only, and only when either myself or the cruise control are attempting to keep the speed constant. Letting off the gas altogether produces smooth engine braking down to undesirably slow speeds, while pressing the gas gives the car a minor "kick" as (what I presume to be something in the tranny) transitions from coasting to accellerating and then runs smoothly as the car picks up speed. The problem is that this "kick" will usually happen several times on a long downhill, which gets pretty annoying to passengers (and probably looks pretty odd to other cars). The car is indeed a 2.2. But what's so funny about going up a hill in 5th? When I hit a 1 mile/2%-ish grade at 75mph, I'm usually only down to 60 by the top of it. I do downshift when I notice the engine bogging or the RPMs shooting up past where they should be for the given speed and gear. Maybe I'm just a low-RPM wimp with a gas frugality complex, but I don't think anyone should be running at 4-5k RPM for normal driving, except when merging on the highway! Quote Link to comment Share on other sites More sharing options...
nipper Posted May 23, 2006 Share Posted May 23, 2006 The car is indeed a 2.2. But what's so funny about going up a hill in 5th? When I hit a 1 mile/2%-ish grade at 75mph, I'm usually only down to 60 by the top of it. I do downshift when I notice the engine bogging or the RPMs shooting up past where they should be for the given speed and gear. Maybe I'm just a low-RPM wimp with a gas frugality complex, but I don't think anyone should be running at 4-5k RPM for normal driving, except when merging on the highway! Nothing wrong with going up a hill in 5th. Some peoples hills are hills, other peoples hills are mountains, and need a downshift. When was the last time this had a tuneup? nipper Quote Link to comment Share on other sites More sharing options...
wondercow2 Posted May 23, 2006 Author Share Posted May 23, 2006 Nothing wrong with going up a hill in 5th. Some peoples hills are hills, other peoples hills are mountains, and need a downshift. When was the last time this had a tuneup? nipper "Tuneup" seems like a meaningless concept on a modern car. I changed filters (except fuel) a week ago, and changed the plugs after a thorough top end and crankcase seafoaming, although the old plugs were hardly worn and were still properly gapped. I didn't change the wires because they looked good, and I have no reason to think the coilpacks are bad either. The problem happened before and after the maintence with no changes. Quote Link to comment Share on other sites More sharing options...
nipper Posted May 23, 2006 Share Posted May 23, 2006 "Tuneup" seems like a meaningless concept on a modern car. I changed filters (except fuel) a week ago, and changed the plugs after a thorough top end and crankcase seafoaming, although the old plugs were hardly worn and were still properly gapped. I didn't change the wires because they looked good, and I have no reason to think the coilpacks are bad either. The problem happened before and after the maintence with no changes. Well a tuneup is not meaningless, all that is gone is the ditsributor. you still have an air filter, spark plugs, pcv valve, fuel filter ignition wires and spark plugs. You can still check the ignition timer to see what the knock sensor is doing. Wires can look good, but thats not how you tell. The ingition system is (and always was) finiky in a car. It can look for leaks at just odd times and take advantage of them. High voltage can be an odd thing to figure out. The engine compartment is a very hostile area for high voltage cables, and thier faults cant always be seen. It can also be themass air flow sensor being dirty or dying. Can be the EGR valve. http://www.2carpros.com/topics/surge.htm read there and see if that helps. nipper Quote Link to comment Share on other sites More sharing options...
keltik Posted May 23, 2006 Share Posted May 23, 2006 Hmm from the sounds of it my guess is now either O2 Sensor or IAC motor. In my old mans rover the engine would take a cople extra seconds to return to idle and would surge a second after touching the throttle - new sensor fixed that problem. As for the IAC this is definately the problem on my wagon, hooked up a vacuum gauge last night and can see it moving without touching the gas. Could be worth a try for you? KELTIK Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted May 24, 2006 Share Posted May 24, 2006 How much does the shifter buck when the car is doing this. If the shifter is flopping around, then I'd deffiniatly look into tranny and engine mounts. Quote Link to comment Share on other sites More sharing options...
SuBrat84 Posted May 24, 2006 Share Posted May 24, 2006 I didn't change the wires because they looked good I made this same mistake in my 98 GT. I later discovered one of the plug wires had a "weak spot" in it and was grounding out on the intake manifold.. (I got shocked by it.) It was an auto though, so it didn't buck like you are describing... more like stuttered.. but same symptoms.. Find a multimeter, or goto autozone, take your wires out and test them. I don't remember what the ohms should be at.. But they should all be with-in the same range. Check your differential fluids... and maybe tranny mounts... Edit: (this was at about 60-65k miles on the original wires...) Quote Link to comment Share on other sites More sharing options...
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