mpudz

Thanks for the reply Joe! I still have not figured this issue out yet, but this is an interesting theory. The balancer you're talking about is the harmonic balancer AKA the crank pulley, correct? I will pull it off and see if the key-way and key are worn as you mentioned. I have had an underdrive crank pulley on my car for the past 8 years or so, and the problem started years after putting it on... perhaps that is part of the problem. Would it make sense for the car to only misfire while cruising on the highway thought? Is it that particular frequency that makes the knock sensor retard the timing? Thanks Joe... I've had 2 mechanics and 3 friends who claim to be "mechanics" look at this problem and none of them had an answer!

Could be... it's so hard to diagnose. What are the odds it's the crankshaft position sensor?

So an interesting update on my misfiring issue... I got a new coil pack 2 weeks ago and put it in with no problem. I drove the car and everything felt great... I was 2 weeks in with no CEL at all. I was 100% sure the problem was fixed as I used to get misfires at least every other day with the old coil pack. And then today came around... I was cruising on the highway at around 70mph and lo and behold, the flashing CEL was back in a fury. I ran the codes when I got home and had misfires on all 4 cylinders... something that had never happened before. It used to always be cyl. 1 and 2, or 3 and 4 or some other combination, but never all 4... So now I'm completely lost. The problem is so inconsistent I don't know where to look next for the issue. As always, any ideas are greatly appreciated... thanks.

Very true. When my knock sensor was cracked, I didnt get a CEL but the car ran like crap (low on power due to the ECU putting it in limp mode) and I was getting horrible mileage (around 11mpg).

The car is a 97 Subaru Legacy 2.5GT. However, the coil that is SUPPOSED to be in my car (which has the male ends) is not the one it was manufactured with. Instead, my car has the older ignition coil with the female ends (like the one in the link in my post above). I thought they were interchangeable so I bought a typical 97 Legacy coil (male ends) and it wouldn't fit onto my intake manifold. Why my car was made with the other coil type is a mystery to me...

Due to some misfiring issues, I am swapping out my ignition coil and the first place I checked was RockAuto, where an ignition coil for my Subaru was around $90. Then, I found this on ebay... it's brand new but there's no info about the part brand or anything. The price is $37, a lot less than most other places. Would you guys trust this part? Is there a lot of difference in quality in ignition coils depending on brand? http://cgi.ebay.com/ebaymotors/IGNITION-COIL-PACK-SUBARU-IMPREZA-2-2L-2-5L-NEW-CAR-/230651170309?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3ASubaru&hash=item35b3e18e05#ht_3464wt_1165

Yeah, thank you. I read through your thread about your misfire issues... did you get yours resolved? I posted my issue in detail here: http://www.ultimatesubaru.org/forum/showthread.php?p=1035116#post1035116 ... as you can see it's quite similar to what you described happening in your car.

I thought your car looked familiar... I was "shizznats" on SL-i

Yup that's right. I am convinced it's not the plugs though since the problem didn't exist with these plugs at one point. I will update after changing the coil this coming week... but I'm doubting it's the coil. Is it normal for a coil to fail only at certain RPMs... and wouldn't it be a more consistent issue (as in, happening all the time?) Is this characteristic of how an ignition coil fails? I just ran the code for the latest CEL and it's only a misfire on cyl 1 this time...

there are NGK plugs that are more basic than the V Coppers that fit the Legacy's, but the stock plugs according to my manual for my car are actually the NGK platinum plugs (which are like $12 a pop)

Thanks bstone. I've been running NGK V Coppers on this car since the first plug change I did, so I think the plugs work well with the car - and I was very careful to ensure a proper gap. But when I do the compression test, I'll make sure they look ok. I wish I could run a smoke test, but don't have the tools. I'm seriously thinking of taking it to a mechanic pretty soon... really concerned about destroying the catalytic converter. Do you guys think it could be an O2 sensor? If so, which one is more important to change? (I'm guessing the first one, pre-cat?)

Thanks for the suggestions. I have new NGK wires that I'll be changing soon, but I'm fairly sure that isn't the problem as this misfiring issue existed before the last time I changed my wires (current ones are also NGKs). I did check out my coil pack and it says the primary resistance is 1.3-1.4 (should be about 0.6-0.8) ... but I have a cheap multimeter so it's probably just an inaccurate reading. The secondary resistance is within spec. I have not checked out the ignitor yet so I'll try finding a used one if the new coil doesn't solve the issue (is the ignitor easy to replace?) Good suggestion on the compression check... I'll do that when I change the wires in a few days (can I remove the plugs and put them back in, or does doing that damage the plug seals?) I'm just hoping it's not the valves... I hear this engine should have a valve adjustment around 100k miles and I'm currently at 157k :-\

Hey guys... I'm new to the forum and hoping to get some help with some misfiring issues that have gotten pretty bad lately. Here's the run down: - The car is a 1997 Legacy GT (157k miles) with a few mods (relevant ones being an intake with K&N filter and a header back Stromung exhaust) - Misfires started about 4 years ago, and the CEL would come on a few times a year and it would be random cylinders (sometimes 1, sometimes a pair of cylinders at the same time) - For about the past year, I've noticed that 95% of the time, the CEL comes on while cruising on the highway (5th gear, about 3000-3500rpm) - Within the past few months, when the CEL comes on while cruising on the highway, it is not steady, but flashing... but I don't feel a change in performance. However, at that speed, running on 3 cylinders vs. 4 might not be noticeable. - When I scan for codes, lately it's been either misfire on cyl 1&2 OR misfire on cyl 3&4, so they seem to be occurring in pairs. - Finally, a few days ago I was sitting in the parking lot and noticed that if I give it just a bit of throttle (1000-1500rpm), the car shakes, which is definitely a result of misfires. And of course, the CEL comes on when that happens. The car does not misfire while idling... idle is very smooth. - I'm running NGK copper plugs (just changed about 2k miles ago) and NGK wires. I've got a coil pack on the way just in case that's the problem. That about sums it up... I wasnt too concered about a few misfires per year, but with the CEL flashing often lately, I'm scared to destroy my Stromung cat :/ Oh, and I don't know if the dollar bill test is worth anything, but I did that and get no negative air flow... the bill flutters slightly but it's always positive flow. Any help is greatly appreciated...

Hey guys, My name's Mike... just moved to Texas from New Jersey (not easy to put up with the heat here >.<). I've got a 1997 Legacy GT with quite a few modifications on it... I'll post some pictures later on. I used to be quite active on SL-i.net, but haven't had too much time to spend on the car lately. Now, however, with over 150k on the car, I'm starting to have some issues (random misfires being the major one) so I'm hoping to get some help with that as well as provide help to others based on my many experiences working on my suby.