CEL P0301 what should i do ?
 

On Thursday night, at about 9:45 Pm i was going to take a 15 break from my job and drive around a little bit. I started up the car to let it warm up. The Idle seemed a bit rough. and i had gotten a small amount of gas twice in the few preceding days from a gas station I had never been to before (single nozzle for 87 / 89/ and 91 octane) aprox 4 gallon fill ups. While the car was idling the CEL came on with a blinking Cruise control. :(

later when i returned home i did an ECU reset (probably dumb but i was hoping the cel was a fluke as i HAD to pick someone up in reno the next day) the car seems to have full power, full boost and normal gas milage. [well i'm getting about 3-4 more mpgs then usual, but i'm driving it like a grandma now] :| well friday night comes and i have to pick up a roommate in reno. i had about 60 or 80 miles since i had reset the ecu , and the CEL + flashing cruise came back, but i had to drive home, so i did.

so on the weekend i took my car into autozone to get the code read. P0301 cylinder 1 misfire. the lady told me it Could be a bad spark plug.

I'm going to call to see if spark plugs are covered by the warentee. if they are not i am currently planning on getting them changed. and if that doesn't work , i'll take my car immidietly into subaru (hopefully for warentee coverage)

I don't want to remove the K&N and drive in with the stock box , cuase i've had it on there for 11 or 12K miles and i also don't feel its very honest/ ethical . also I've been going into subaru for service with the K&N installed , so they may have already written down i have it. IIRC a warentee law they have to specifically prove my mod cuased the problem. I don't know enough about cars , and i also don't know if/how an air intake could cuase my problem.

its only a car, but i'm sooo bummed.
please help, what should i do?

Clean you K&N and put it back in, assuming it is a drop in. Dealership won't/shouldn't care if they even look which is unlikely.

How many miles you at? If under warrenty, take it in and make them fix it.

there are an awful lot of things that can cause misfires. You say you are driving like a grandma to increase your fuel economy, which makes me wonder if you fouled a plug. Raise your shifts points a little and give it the old Italian Tuneup and see if that clears it for a while.

If you're still inside of the 3yr/36,000 mile period, take it to the dealer! It should be covered, unless, like you said, they can PROVE that some mod you've done has caused the problem. I doubt it tho. There's about a hundred things that can cause a misfire, so it's hard to point a finger.

Intakes, which skew MAF readings by design, kinda fall under that category. they don't HAVE to blame the intake for the misfire, but if they do nobody can really argue with it.

19,xxx miles . Its a short ram air intake kit (cone)

Sorry I meant that After the 1st CEL light came on i've been driving like a grandma.

New subaru oem plugs are $16 a piece. i called south shore motors for a price. I asked it it would be covered under warentee and he said he didn't know. he also said they would not look at it with out the CEL on. i asked if should drive carefully, avoid WOT or rpms over 4K and he said no. drive 100% normal on it until the CEL comes on again ... :| (i don't fully trust them for service as they did a poor job servicing a 1996 impreza brighton L about 6 years ago . ie did not put the oil cap back on, steering fluid cap, and failed to reconnect the Fans)

i may call micheal hohl to see if they can tell me clearly if it will be covered. i fear south shore motors. [the 96 impreza, and i got Tboned there picking up an oil filter 5 months back]

.... I dont think an air filter would ever cause a misfire. I agree that it could be a bad sparkplug, bad ignition wire/ignition and/or bad gas.

micheal holh at Thursday 8:00 am. that lady said becuase i'm with in 36,000 anything should be covered. i told her i had a k&N and she then told me she would pretend she didn't hear me say that. :| i asked if i should remove it and she said no just leave it as is. :| Does anyone know if micheal hohl has a history of giving modders a hard time? i can put the repair costs on my CC and fight for warentee coverage worst case but obviously that will suck.

(assuming Rubber Buscuit can help me change my plugs) should i try changing my plugs ? or don't touch anything and take it into subaru ? [i'm going to go with the prevailing advice]

Micheal Hohl denied replacing my axle grease under warrenty (is was the wrong type of grease used by the factory) because I had an exhaust and a "group B rally" sticker on the rear window. :roll:

Bet they were still better than Lithia who refused to even test my bone stock car for a known clutch issue that Michael Hohl did replace under warrenty.

IMO, all dealership service departments are shady... unless you know someone working there that you can trust, I wouldn't trust 'em to do a job straight. Hell, I'd bring my subaru to Nissan before I'd bring it to any Subaru dealer, simply because I'd trust Cory to do the job right.

As far as the intake... take it off before going to the dealer. I had the service manager at Michael Hohl actually tell me "you should have taken off the exhaust before coming here, but since you didn't, and since it's already in the service write up, I can't help you."

Also, once you take off the K&N, don't bother putting it back on until you get the ECU reflashed for it, all you're doing is leaning out the car which at the most does nothing because of our altitude, and at the worst creates a higher chance for detonation.

Also, I wouldn't put a K&N back on at all even w/ a reflash, since they use animal fat in the filter element and many people have had issues with 'em screwing up the MAF sensors. I know I had a MAF go bad on my SVX... I can't totally pin it on the K&N drop in filter I had 'cause the car had over 200k miles, but the failure was right in line with the type of failures others have seen w/ K&Ns. Plus, they really don't flow all that much more than a cheap clean paper filter, and they certainly don't filter any better.

Swapping the plugs is a bitch of a job... at least compared to other cars. You'll have to take the battery, intake, and washer fluid tank out, then use a ratchet w/ like 9 extensions and a spark plug socket on it to get the plugs out. It's a real PITA for what's a 10 second job on most other cars. If the plugs really need to be swapped at less than 36,000 miles, let Subaru do it. Plus, if they cross thread something (which isn't that hard to do w/ the soft aluminum heads and all those extensions) they'll be responsible for replacing the heads, and not you.

If you are gonna deal with South Shore Motors, talk with Dayton Lee. He is the head dude in charge.

I worked at SSM back in HS and I trust that guy's advice. He flat out told me to take my car to another place for a 30k tune-up. Because I wanted them to put in Redline Shockproof in the tranny. He told me that other places won't keep track of what they put into the car, just that the fluids were replaced. Redline shockproof will void your transmition's warranty.

Hey! I do appreciate the good word Scott!

I can say for sure that K&N filters do screw up MAF sensors. NOT all the time, but I've prob. seen it about a couple hundred times here. Nissan MAFs are so sensitive tho, you can give them a hard look and fry them! I don't know that subi MAFs are as sensitive, but the K&N has a bad rep around here...

Usually on Nissan cars, if you do end up with problems from a drop in or ram air filter, it turns up pretty quick. Not the 11,xxx miles later you've got on your kit Alex, but again, that COULD be the problem. The way turbo Subis run lean without a reflash, it may be something that's just been a long time coming, and only now have you managed to run a plug lean enough to start causing CELs.

If it does turn out to be plugs, and they won't cover it, lemme know, I can prob. give a hand with replacing them. It's a long drive, but you get professional service!

thanks All very much for the help / advice.

By reflash you mean a proper EM and Tune ? (then no i did not, i did reset the ecu after install, and after my remod)

as advised I'll put my stock breather box back in. (will just the breather box be okay? i've removed the silencer chamber, and i cut my snorkel (now thinking that was a dumb idea)

(i will reset the ecu after going back to stock)

I'm tempted to take up Cory on a spark plug switch (Esp if i can do that before going into subaru) as south shore said spark plugs are wear and tear items / no coverage for that :(

Spark plugs are a wear item, like belts and brakes, but if there's some circumstance that's caused them to fail prematurely, that's covered by the warranty, then the plugs are too.

I'd say take it to them, and let them say what they will. If they do cover it, COOL, if not, and you do end up needing something that you don't dare to tackle yourself, I can help!

I have never heard of any dealership covering spark plugs under warranty.

I work at one that has. Think about it: If you have an ignition coil, or a fuel injector, or a MAF that fails under warranty, and thus fouls one or all spark plugs, then the plugs are covered as well as the part that caused their demise. Such as a belt that gets frayed by a pulley with a bad bearing. Both the pulley bearing AND the belt get covered.

Plugs, brakes, belts, etc. that just plain wear out, like they're designed to do, are NOT covered under warranty, but when they fail prematurely, they are.

now that i've spent the time to pm you back, it looks like everyone else already explained it better. but i'll post whore it anyway.

Egg zachary.

OK, I stand corrected. Now I have heard of a dealership that will cover spark plugs, under certain conditions.

HEHE

I hope mine are covered if that is the problem. $60 in spark plugs and 1 hour labor wouldn't be that bad of a financial hit. (well i don't know what they charge for labor ) :(

Spark plugs should be covered on every warrenty where they fail before their reccomended service interval which is often longer than the warrenty period these days.

Oil of any kind, animal, vegetable, or miniral can FU a MAF.

Most of the K&N related MAF isues I have heard of have been related to recharged ones where the asshats didn't read and/or follow the instructions and tried to do a recharge in < hour, and/or used more than the reccomended amount of oil. The filters have to be completely dry before you oil them and most idiots won't wait that long.

I've done enough now that I often end up with a correctly coated filter before the reccomeded amount by a 1/0th of an ounce or 2. I have 3 MAF cars with them, and 5 or 6 recharges and never an issue.

I like them and was thinking about building a cardboard heat shield for a couple of them. :)

I thought Alex's MAF might be an issue, but he has had the intake for a long time, and IIRC he just cleaned it very recently.

Mazda covered it for my blue rx8, they had a hard-start condition that was documented in a TSB.

Uh-oh... Hope that isn't it. No insult was intended by my previous post.

That's the thing tho, with Nissans anyway, is that for some reason, they are SUPER picky, and I've seen TONS that crap out with no oil from the filter on them. As soon as you drop the new, factory oiled filter in, you get a CEL. Maximas and Sentras are notorious for this!

Kind of Apples and Oranges, Nissan and Subaru, but IF the Subi MAF is nearly as sensitive, I could see it being the problem. I'd like to think it may have shown up sooner tho...

But Alex isn't seeing a MAF CEL, he's got a misfire. I'm more apt to blame the problem on the higher air-flow leaning out the car and messing up the plugs over 11k miles than to blame it on the element's oil.

The issue w/ the K&N element was more of an aside as to why I wouldn't re-install that particular intake, even if he were to get the car re-tuned for it.

When i remoded my Intake i added aditional heat shielding (i have spare sheet metal if you want it dean, although since i paid like $3 ish , and i'm trying to avoid driving as much as possible, its cheaper for you to buy some, then to pick it up in tahoe - though if Brian ends up here for work maybe i can hand it off and it will make it to a meet?)

I have not yet recharged my air filter. i was just thinking the filter was about due. But now its about due to be pulled off for the stock intake. :( [tonight if i can borrow tools / if not , way soon]

Sucks to be wrong.
its even shittier to be wrong with a broken car :(

(to bad that i LOVE the motor/turbo noises with that intake\ though not enough for motor damage) After my car is fixed Maybe i'll hunt down a different filter/ intake (Only when i can get EM + Tuning directly after)

I really hope Sperry is right.

is it likely that i've cuased permanent motor damage ? :(

Maybe your intake temperature is too low

Very unlikely. Like I said, a million things can cause misfires. I used to get them in my RS after I did the Exedy flywheel because the ECU couldn't accept that revs were suppose to rise and fall that fast off-idle. :p So, replacing plugs and your stock airbox *should* fix the issue.

A few misfires isn't (shouldn't) gonna break anything. I've plain old unplugged the fuel intector signal wires while testing my motor for issues. Car idles like a pile, but it's not gonna break the motor unless you go out and romp on it, and even then as long as it's not detonating, it's not the end of the world.

It actually may be something as simple as a loose connection on the spark plug or fuel injector... any chance you bumped anything while working on the intake?

Yes there's a chance i bumped into things. i had a hard time sliding my new heat shield in and out. although my hands and the shield were only the ABS side of the K&N shield. the only items i could see that i had to worry about was the ABS brake lines. i can't rule out that i did not elbow or bump into something.

I'm not sure where my fuel injector is or what it looks like. maybe i'll bug Ansel to give my engine area a visual once over.

Maybe Mike, i really don't know :(

I did do 3 things directly before seeing the CEL. Remodded, filled up at a different gas station, reset the cu
i did read on howstuffworks.com how the MAF sensor works. according to the interweb, new model subarus , heat up a wire to a given tempature, and then it reports to the ecu how much voltage is required to heat up that wire to what ever given temp they use. so if your intake system cools that wire down more then the stock system, it reports a higher voltage. if your intake system does not cool down the wire as much as stock , then it reports a lower voltage. (more reasoning why everyone was correct that changing the intake requires a tune, or going back to stock)

Your understanding of the MAF is essentially correct. There are "hot wire" and "hot film" style MAFs, as well as old school "flapper door" types.

flapper door? sheez even air flow is confusing
and i'm up to about 50 miles now since the CEL clear, the CEL has not returned (i'm sure the problem is still there though)

That's kinda what I was saying, however unclear... :lol:

I would def. say it's more likely to be the lean condition, than the filter oil taking out the MAF, since it took 11k to show up.

I think I thought the part I was supposed to type and typed the part I was supposed to think. :?:

400 miles since i got my CEL cleared at autozone and it hasn't come back ?!? when i took my car into subaru i was at about 300 miles, and the service guy (Jerry) said he's seen a number of subarus throw a few CELs due to bad gas. He said the ecu can retarded the timing so much you get a misfire. he said if it threw the CEL just to come right back in and i won't need an appointment since i came down once.

I did get gas from a different station (american gas in tahoe) twice before i got the CEL. the last time being about 10 or so miles before the first CEL ...

:|

"Bad gas" usually means "we don't know what happened, here's a random meaningless explanation for you."

They might as well have told you there was a tiny unicorn poking holes in your exhaust and shitting in your filters.

Actually, STI's are pretty sensitive to gas quality. Ask MattR about a particular 76 station in Livermore... we left that place making popcorn under the hood.

They should have put it on an oscilloscope to check if your ignition system is working correctly. You can spot a bad plug/coil that way.

That was awlful.

hmmmf. I'm still confused. it does seem to be running a bit smoother now (400 miles later and fill ups at different gas stations)

I took the engine up to 6K repeatedly going to and back from truckee since then, no CEL. I'll make sure to get my 30K service early , chalk it up to bad gas , unless there are other recomendations someone may have ???

Oh and lucky me ! I ran over a nail or something on my way down , or while in carson. when i left the subaru dealership my back end got very fishy on me so i stopped to check tire pressure. Driver side Rear was flat :( i pumped it up to 38 , drove across town and it was down to 32. drove up to tahoe and it was still at 28 at my house. i tried some fix a flat stuff, and refilled it to 36. but the leak got worse and it went all the way flat. So i'm back on my snow tires for a week or two (had to pick a friend up @ truckee that day)

hopefully i can stop wrecking my subaru for a week or two here. :|
[as per suggestions i'm off the k&N too]

CEL came back. went in today. bad coil pack. they have to order it, should come in friday. :|

Now you're getting somewhere. :)

Simple fix, and covered under warranty! Can't beat that!

If you really miss the K&N, sell it and buy this. :D

Actually I was wondering how much quieter is the intake now that you have gone back to stock (minus the silencer)? I assume power feels the same?

new coil pack installed. idles a bit smoother. car seems happier (and i am too) :)

Nice find Cody!, i saw the one for the legacy GT 2.5 and asked in the subaru parts department if they had one for the sti but they did not.
Its much quieter back on the stock intake box, and the first plastic air peice + an elbow. but the car is still fun to drive but all the great turbo noise / whine is gone :( (honestly i hate the stock lack of noise in comparison) i may put the K&N back on for winter / after the rallyx events are all done.

That elbow holds back a lot of noise. Most people don't bother with it. But since you're rallying, you may want to keep it.

It came back. taking the car in thursday, don't feel like taking the day off of work to sit at subaru (again) , and they don't have free loaners anymore (or so they said) so i think i'm doing a $20 a day rental , so i can get groceries after i get paid (tomorrow) then i'll drop off the rental cuase driving in tahoe, over the 4th of july weekend is useless.

Arg no car for the extended weekend ... :( lame


with how my car luck is going, i'm thinking i'll be buying the extended warentee pretty soon .

Which is going to be a massive waste of money if you continue to rally-cross it. I don't care how stock the car is, you're gonna break something big and expensive and Subaru is going to (rightfully) deny the warranty due to you driving it so hard.