misfiring

[Burtonboarder950]

My check engine light turned on today, just what i needed. I brought it to my friend who has a scanner and told me my error is a P0300, meaning my engine is misfiring. I have a two week old nismo cold air intake, which might be it. I dont like the little bursts of air coming out of my exhaust caused by the misfire. The scanner said it could be spark plugs (i really hope it is), bad 02 sensor, catalytic converter, a huge list which didnt help any. Any of you experience your Z misfiring, or have a better idea to what my problem could be? I am very upset about this...any ideas?

[dasoupdude]

I'll put my money on a worn spark plug.

[Burtonboarder950]

I'll put my money on a worn spark plug.

your optimism just made me feel a lot better.Does misfiring hurt the engine the long run...will it cause me problems? Only been misfiring for about a weekish that i noticed. Didn't think it was actually misfiring that i was hearing until my friends scanner said so, but its faint.

[dasoupdude]

your optimism just made me feel a lot better.Does misfiring hurt the engine the long run...

See that's not something you don't want to project on doing "in the long run" but more like in the "now run." Worn out plugs will really mess with the overall performance of your car and you'll end up having even worse fuel economy.

So basically if it is indeed one of your plugs that is acting up, your basically running on a 5 cylinder car right now.

Think of it as a 6 legged horse running only on 5 of his legs...?

[rmezz13]

Think of it as a 6 legged horse running only on 5 of his legs...?

LMFAO. You could just said a 3 legged dog, i'm sure he's smart enough to get that analogy, but you had to say the 6 legged horse - made it worth reading!

[Burtonboarder950]

LMFAO. You could just said a 3 legged dog, i'm sure he's smart enough to get that analogy, but you had to say the 6 legged horse - made it worth reading!

I'm glad he didn't say three legged dog because i feel so bad for those things. And wouldn't a six legged horse with five legs still be better than a normal four legged horse? Why feel bad for a horse that has two legs over all the others horses?

and i know what you mean...im seeing a mechanic on monday

[rchboy]

when was the last time you filled your tank? same station as you always use? if i remeber corresctly po300 is juat general misfire if its not defined to be on a certain cylinder. watery fuel may be the cause. at my old job i used to come across bad fuel a lot more than ignition components failing. thoose cars were of a different manufacturer though.

[Burtonboarder950]

when was the last time you filled your tank? same station as you always use? if i remeber corresctly po300 is juat general misfire if its not defined to be on a certain cylinder. watery fuel may be the cause. at my old job i used to come across bad fuel a lot more than ignition components failing. thoose cars were of a different manufacturer though.

HEY!I have been broke recently because I have been out of work for two weeks (starting work this week:) ). I have been driving between empty and one quarter for about a month. I would fill up wit $5 when ever the light was ready to turn on, and it was an endless cycle. But this started last night when i was at a quarter. Any possible relation?! thanks

[rchboy]

you could have sucked all the crap out of the bottom of your gas tank and partially clogged the fuel filter. has it ever been changed before, whats the mileage on your z?

[Burtonboarder950]

there are thirty thousand miles on the car, but ive only owned the car for 1,200 miles. That is a good theory that I got the the **** at the bottom of my tank into my filter. But could a clogged filter cause misfire? Ill change the plugs, oil, and filter monday

[xjmxstac]

you could have sucked all the crap out of the bottom of your gas tank and partially clogged the fuel filter. has it ever been changed before, whats the mileage on your z?

The fuel pump is at the bottom of the tank. If there was crap in there, you would've sucked it in a long time ago. I'd check for bad spark, bad o2 sensor, or perhaps plugged injector(s).

[Burtonboarder950]

The fuel pump is at the bottom of the tank. If there was crap in there, you would've sucked it in a long time ago. I'd check for bad spark, bad o2 sensor, or perhaps plugged injector(s).

how much do 02 sensors cost, and how many are there? im not too familiar with them

[xjmxstac]

There's two, I believe. One before the cat and one after. They cost anywhere from $60 - $140.*edit* It can be a little tricky to remove them without f'ing it up. See when the engine (specifically the exhaust pipes) is cold the metal is in a "relaxed state" making the bung where the O2 sensor sits very tight (in some cases impossible to unscrew). So, if you know someone with a twin post hoist or similar apparatus to get your up high in the air, you can warm your engine to operating temperatures turn it off and unscrew the O2 sensor. It will still be fairly tight but not impossible to unscrew. A lubricating agent might be necessary. Take note that at operating temps, you cars exhaust pipes are extremely hot. I wouldn't even try to crawl under a car with hot exhaust pipes. The other way to do it is to get a torch, heat around the bung and unscrew. Again, you will need a decent lift on your car. The only downside to this seemingly easy method is that there's a chance that you can overheat the bung and/or your sensors and foul them up. Unless you're exactly sure which one is faulty, or you're replacing both of them anyway, the second method requires a certain level of experience and skill. Good luck!
Modified by xjmxstac at 2:22 PM 9/21/2008

[Beancooker]

your optimism just made me feel a lot better.Does misfiring hurt the engine the long run...will it cause me problems? Only been misfiring for about a weekish that i noticed. Didn't think it was actually misfiring that i was hearing until my friends scanner said so, but its faint.

Running with a dead spark plug will also cause more raw fuel to go into the cat converter, and will foul it a lot quicker. When the plug fouled, you start smelling a fart smell from your car?

[Burtonboarder950]

nope no smell. My moms plug worn too with the same symptoms...also no smell

[xjmxstac]

nope no smell. My moms plug worn too with the same symptoms...also no smell

That kinda sounded a little funny...no offense! But I know what you mean. Fart or rotten egg smell come from the catalytic converter going bad that could be due to unburned fuel getting through the system like beancooker mentioned. If you are attempting to do this yourself, just go through the list of probable issues that might be causing your misfire. Check each component and replace parts if needed starting from the cheapest one. It really sucks that the OBD doesn't really tell you anything but misfire codes and there is really no easy way of pinpointing exactly what is/are fouled component(s). It could be one part or a combination of different parts. I'm still going through the same process with my toyota. Codes say that i have multiple misfires. I have had my injectors recently cleaned and my fuel filter replaced. I have changed all my spark plugs and coil packs and is still misfiring. But at least i know that its not my ignition system or my fuel delivery system. I am now gonna go to the O2 sensors and the catalytic converter. I got about a month and some odd days to fix it until my scheduled smog test to be able to re-register the car for the next year. SH** I need to get moving its almost october!

[Burtonboarder950]

Good news! Went to a recommended auto shop today and installed some ngk premium platinum spark plugs. They wound up being the stock ones too, so what is better for the engine that stock? Just letting you know that next time you want to replace your plugs. I also got a full throttle body clean out and the engine is running a lot smoother. I still get a random clucking noise though, i think we discussed it already and decided that its the transmission but it only clucks when the car is at a stop in neutral. You guys hear the same noise? And if it was the trans, why would it cluck in neutral? thanks, zack

[dasoupdude]

Because Borg Warner enjoys watching us suffer, just ignore it. Even the GT-R's transmission makes noises too, customers have to sign a waiver which states they will not complain about brake or transmission noises.

[Burtonboarder950]

so do you guys experience a clucking noise in neutral too? This is very important because if its only me ill have to go to nissan and spend money i dont have lol. Please let me know if you experience a clunking noise when in neutral, im not talking about when changing gears. Thanks in advance as always, Zack