So i scanned my car, and pulled the following codes:

P0300
P0302
P0304
P0305

My gas mileage sucks too. 05 TL auto.

 

P0305 Code - Cylinder #5 Misfire
P0304 Code - Cylinder #4 Misfire
P0302 Code - Cylinder #2 Misfire
P0300 Code - Cylinder Misfire

Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.

A P0300 OBD code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.

Symptoms
Symptoms may include:

* the engine may be harder to start
* the engine may stumble / stumble, and/or hesitate
* other symptoms may also be present

Causes

A code P0300 may mean that one or more of the following has happened:

* Faulty spark plugs or wires
* Faulty coil (pack)
* Faulty oxygen sensor(s)
* Faulty fuel injector(s)
* Burned exhaust valve
* Faulty catalytic converter(s)
* Stuck/blocked EGR valve / passages
* Faulty camshaft position sensor
* Defective computer

possible solutions
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

all info from
http://www.obd-codes.com/P0300

 

Thanks for the explanation. But theres another problem i failed to mention. When we tried to cancel the errors, it said it wasnt able to, so not sure if that says anything.
My car idles fine, starts ok too. Only problem i have is with the gas mileage. I get about 425-450km to the tank, and thats 60 city 40 hwy.

 

csmeance is right on! If you smell your exhaust and it smells like fuel.. then that's where all that extra gas goes. When you get a CEL the ECU says "hey.. something's not right" then it runs rich and burns more fuel which pushes out through your exhaust to protect the engine integrity which is why your gas mileage sucks.

Can you give us some additional details.

How long have you owned the car?
How many miles?
Have you done any maintenance recently?
Anything happen to your car recently?
What type of scanner are you using?

You can reset the codes by either unplugging the battery (make sure you have the radio code!!) or fuse (I forgot which one though.. search).

I would definitely not be cruising around if you are getting misfire codes. Sometimes a misfire can be subtle until your valves get turned into pretzels. I'm pretty sure we have interface engines.

 

misfiring is pretty common with many tl's I was recently getting similar codes and had all coil packs and plugs replaced under warranty and they havent came up since.

 

I picked up the car used about a month ago. it has 138KM on it. The light came on after a few days of ownership.
I havent done any work to it yet. But as far as the exhaust goes, it smells just like fumes.
Not sure if this might be helpful, but i hear some sort of a ticking noise sometimes when driving, especially when the engine is cold.

 

I knew it... as they say up there.. sounds like you got hosed, eh! but don't fret just yet.

The dealer / private party probably sold you a car with known issues.. cleared the codes so you wouldn't notice and then boom.. ECU recognizes problem and you get codes again after you bought it and down the road a bit.

At those miles your are very close to doing big time work like new plugs, timing belt .. yadda yadda = $1k to $2k depending on if you do it yourself or who you go to.

You should take it to a dealership. Have them diagnose engine. Don't drive it too much. It could be very simple to very expensive, but for sure at those miles you should at least be doing the plugs and new PCV valve / adjust.

You should get it checked asap in order to get some comp.. because the longer you wait.. more damage and less liability to the party who sold it to you.

 

most likely thing is a single coil pack has failed, the codes say multi cylinder but are wrong~
They let you know there is a problem
Bad gas mileage means all the fuel is not getting burned

Pull a front spark plug and check its condition for wear
Buy 1 coil @ $50 and try it on each cylinder (start with the one the computer thinks is bad), reset the ecu and start car,,,move to next cylinder as needed- reset ecu each time- find the correct coil and stop

If you are going to change the plugs now, the plug thats black and wet is the bad coil cylinders coil

 

Not all scanners/readers can cancel codes. They all can read them, but the cheaper ones can't cancel the code.

 

I think taking the plugs out shouldnt be too hard to do. i worked on my maxima before, that was a job and half.
Anyway, is there some sort of online repair manual to follow?

Many thanks to all the contributors.

 

good luck and hopefully its similar to the problem I had or what 0104tl has said.

 

I have the same issue. (P0302) Smells like fuel to me. When I clear the code, it stays away and I drive about 100 miles a day. My only problem is that it stalls on me when it is cold. I need to check all the vaccum lines. I swapped all the coils around and put in new plugs last month. I think I need to bite the bullet and order 6 new coils.

I ordered a new PCV valve today and I should get it on monday. Figured easy fix. We will see if that solves the problem. Just trial and error.

The price of commuting to work....

 

Oh man that sucks.. does it stall in idle or on a cold start?

When you say swapped the coils do you mean you moved them around or you bought a single coil and tried one by one to find a bad coil? hmm.. I'm sure you checked but have you checked to make sure the wire harness connection to each coil is secure.

I'd definitely follow csmeance's recommendations but it sounds like your already headed down that path. The only other advice I have to offer which was part of the problem in my install is the electrode from the coil that fits over the plug is spring loaded. When you place it over the plug, carefully adjust side to side until you hear it snap in / click... otherwise the electrode will push itself off with greater force, and even with the coil screwed in this may cause a weak connection. Wrench in the coil once it snaps in.. the rears are a bit tricky to detect.

 

I just moved the coils around. I have narrowed it down. It is the rear center that is bad. The coil is not bad though. Did a test and had the car running and unplugged the coils and I was able to notice a difference in the engine idle when unplugging the coils. Thought it was the coil and moved it round again and it was still no difference when I unplugged it.

I am thinking it is the fuel injectors but not sure. Really don't want to pull the whole engine apart to find out that its not the injectors.

 

Have you used a fuel-injector / carb cleaner yet? A lot of people swear by seafoam. I have yet to use it but I have always used and trusted Berryman's B-12. I put a can of that in my tank after a fill-up and I definitely noticed a difference.

It might be an inexpensive way to clean your fuel-injectors. They sell that stuff at Carquest and maybe Pep Boys. Be careful and keep that stuff away from the paint.. use a funnel. The new bottle has a real long neck so you don't need a funnel.

I suspect something very simple. Keep this thread updated. I'd like to know what it ends up being.

 

I put a bottle of the seafoam in the gas tank when I was about half full. Didn't notice a big difference. The problem still exists. I am going to pick up my PCV Valve today and replace it.

Friend of mine used to work at Acura and said that the idle control sensor might be bad and to clean the throttle body. Going to check those out before I tear the motor apart.

 

i have replaced bad ignition coils.. also on these TL, there is a crank pattern that the pcm goes by to monitor misfires so if that haven't been performed properly or the battery recently went dead then the crank pattern might be thrown off and will need to be cleared and relearn again with the honda diagnostic system

 

Any update?

 

Ok, so ive decided to replace the coilpacks, 02 and plugs as a maintainance routine; but the problem is, we in Canada are getting RIPPED off with the prices.
i was quoted 150 for a coilpack. and 400 for the front 02 sensor.
Are there any sites i can order these from?
Thanks guys.

 

No new updates. Haven't had time to clean out the throttle body.

 

There are a few sites that are offering 20% off parts but don't know how much it will cost to ship to you. oaklandacura.com is a local place that I am aware of.