Misfire troubles continue.. need suggestions

[d1giPhux]

Okay.. so.. looks like the car is back to mis-firing. Now its misfiring in cylinders 1, 2, and 3. It seemed to stop for a while after replacing the coil / spark plugs / wires. I then seafoamed my car.. and the CEL light turned back on. I thought this was just because of the seafoam.. but last night.. the CEL was flashing.. so i decided to check it again today. Engine misfiring in cylinders 1, 2, and 3.

I'm really not sure what is causing this.. but i need some ideas as to what else to look for. So far this is what I have replaced:

Spark Plug Wires
Ignition Coil
Spark Plugs
Intake Filter
pcv valve
Changed Oil
Seafoamed engine

All of this seems to be happening ever since i got my new cats put on the car..

Any suggestions would be greatly appreciated. Thanks.

[d1giPhux]

Here is a super long extended log i have been keeping since the problems started happening..


1. Brought car to Subaru Dealershio and had them check exhaust for exhaust leak. Leak was found around second catalytic converter.

2. Drove car around for a while with minor exhaust leak, until bend in secondary catalytic converter finally blew out causing a much larger hole.

3. Took car to exhaust shop and had both catalytic converters replaced with parts I provided. Universal OEM spec cats, and 2 brand new Denso OEM Spec Oxygen sensors.

4. Received car back from exhaust shop, but was not impressed when the muffler sounded louder, and also seemed to shake more at idle and gurgle while in the low RPM range.

5. Car continued to idle more violently while sitting, and also seemed sluggish in LOW rpm, and continued to make more gurgling / rumbling noise.

6. CEL light goes off with misfire in cylinders 1 and 3. PO301, and PO303. I drive it around for a bit after resetting the ECU to see if the misfire code goes away.. it continues to stay on.

7. Replace Spark plug wires in hopes that the misfire CEL goes away. Reset ECU, but the CEL comes back shortly after about 30 minutes of driving. PO301, andPO303 continue to exist.

8. Replace Ignition coil, and reset ECU. CEL Light seems to go away, however car is still sluggish in LOW rpm range, and also still loud sounding, and makes gurgling sounds in LOW rpm range.

9. I drive the car around for an hour, and while driving around.. I get a new exhaust leak. Since the catalytic converter (front) has 2 o2 sensor bungs, the second was plugged with a cap that was never tightened down properly. It blew out, and I drove home for about an hour with an ‘exhaust leak’. I replace the bolt (M18x1.5), and the exhaust leak sound goes away.

10. Car continues to smoke more than usual, sounds louder than usual, and is still sluggish in LOW rpm range. Also seems to idle much rougher than usual until warmed up. Noticed water coming from exhaust after sitting for a few days.. but this may be normal condensation. Wondering if the plugs may be fouled from driving around with the misfire for a few days?

11. Replaced all 4 plugs.. idle seemed to smooth out a bit.. bit more power at 3000+ RPMS.. besides that.. still sluggish in LOW rpm range..

12. Seafoamed engine for carbon build up, also replaced pcv valve. Didn’t notice much of a difference in performance. Sluggishness occurs as follows:

2k-2.5k RPM Range: Very sluggish, almost no torque, stuttering feeling when trying to accelerate.

2.5K-3K RPM Range: Sluggish, bit more response.. but still no torque or ‘pull’ when accelerating’

3k-3.5k RPM Range: Acceleration is decent, does not feel too sluggish / does not stutter much.

3.5k – 4k RPM Range: Acceleration feels normal, definitely ‘pull’ in terms of accelerating.

13. CEL came back. PO301, 302, and 303. Misfires in cylinders 1, 2, and 3. Here we go again.. back at square one.

[sexystover]

do you have a test light?

if so you can check to make sure ur getting correct sprak constantly at the wires and then if not go farther up the line untill u find the cause

[decke48]

vaccum leak

[d1giPhux]

thats what im guessing.. but i dont even have a clue where to start looking for one / how to look for one? Any suggestions on that? Also.. any clue why replacing the coil / spark plug wires may have helped initially? It seems like that fixed it for a bit.. and now its back. At first it was only cylinders 1 & 3 misfiring.. but now 2 is also misfiring.

[1996Battlewagon]

There are so many different ways to test a vaccum leak it's silly. Just google vaccum leak test, and find a way that suits you. I've done it with a simple vaccum gauge and went for a test drive to see what the vaccum preasure was doing.

Your timing isn't off, is it?

[d1giPhux]

Yeah.. the timing should be correct.. i dont think it jumped or anything. I'm not really sure WHERE i should be looking for a vaccum leak i guess is what im saying..

[jey]

Start with the intake manifold. There are a couple of hoses that attach to the back of it that go to the EVAP system and other sensors. Then work your way up - there are other hoses that attach to the intake tract from the air filter box to the intake manifold.

I didn't see a fuel filter on the list - that's a cheap easy one that you can replace to rule that out too.

[d1giPhux]

Yeah, I didn't get around to seeing if the fuel filter was bad or not.. one of the things i didnt do. However.. seems like there is enough fuel getting to the car.. as my exhaust smells a bit like unburned fuel when it misfires. However... its going to the shop today, as the daylight hours are getting to be less and less, and its starting to get colder.. I really just don't have anymore hours to dick around with it at the moment. I will keep this thread updated to see what the outcome is.. and what they think the problem may be. :smt009

[d1giPhux]

So.. bit of an update on this situation.. in case anyone runs into this in the future. Took it to the subaru shop.. and here is the diagnosis:

-Timing skipped 1 degree or so on both the upper and lower cam. Since they were the last ones who did the timing belt for me.. just this past january.. I'm pretty sure they are gonna be cool about it and just split the costs with me (so they said.. however.. when i asked them for a final price.. they didn't even mention charging me for it.. which is awesome!).

At the same time.. I'm also having my oil pump resealed.. woo hoo!

So this story didn't turn out to be too bad just yet! Just need to wait till i get the final bill to see what the damage is!

[Huffer]

Good to hear. I think I would be a bit concerned that the timing belt was able to skip... it shouldn't do that easily.

[d1giPhux]

any reason why that might happen? hmm.. does seem a bit strange to me.. but.. I'm really not sure what to make of it.

[Huffer]

incorrect tension, stretched, defective belt. Could have been a lot worse, if the belt snaps you get bent valves.

[decke48]

they set the timing wrong. i see it happen all the time. 1 degree? you mean 1 tooth? because a tooth will set the timing of about 5 degrees

[Huffer]

they set the timing wrong. i see it happen all the time. 1 degree? you mean 1 tooth? because a tooth will set the timing of about 5 degrees

Thats also a strong poss. I do find it weird that digi didn't notice any rough running until after his cat install though.

[LegacyRob]

Probably a bad timing belt tensioner and it was just a weird coincidence that it happened the same time as the cat.

[d1giPhux]

The belt has already snapped once before.. back last winter.. thats when they changed it out for a new one.. and that was because the tensioner went. I had them replace all the pulleys / tensioners.. the belt.. and a whole lot of more expensive shit.

My guess is.. it was set wrong.. or the belt is defective or something.

And yeah.. i meant one tooth.. sorry for the weird terminology.. I don't know too much about setting the timing myself.

I hope when they fix it.. it wont become a problem again in the future... I'm also hoping that they follow through with that they said and eat the bullet on this one.. since I already paid to have it done once.