The CEL/MIL light just came on and the code reads P0302 Cylinder 2 misfire. The car has about 37K miles on it. What is the significance of this? We have an appointment at the dealer next week to have it checked out.

 

Maybe just a bad plug or a batch of bad fuel...

 

What does that mean?

A P0302 code means that the the [FONT=Verdana,sans-serif][FONT=Verdana,sans-serif]car's [/FONT][FONT=Verdana,sans-serif]computer[/FONT][/FONT] has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #2.
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 P0302 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned [FONT=Verdana,sans-serif][FONT=Verdana,sans-serif]exhaust [/FONT][FONT=Verdana,sans-serif]valve[/FONT][/FONT]
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• 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 [FONT=Verdana,sans-serif][FONT=Verdana,sans-serif]car[/FONT][/FONT], 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 [FONT=Verdana,sans-serif][FONT=Verdana,sans-serif]fuel [/FONT][FONT=Verdana,sans-serif]injectors[/FONT][/FONT]
.

 

http://www.obd-codes.com/p0302

 

Thanks. The engine seems to be running OK. I think if 1 of 4 cylinders was out it would be very noticeable. No other symptoms apart from the CEL/MIL. It's only 1 year old so no obviously bad components either.

 

My cars 3rd Cylinder misfired. They replaced the ignition coils and the spark plugs and the issue was resolved. Hope it gets all fixed for you!!

 

I spoke too soon. At low revs and at idle the engine is lumpy sounding. Starts and runs, but sounds rough at idle. Also there is black soot blowing out the exhaust and the occasional pop comes out the pipes. Also, it's low on oil.

 

Oh dear

 

You haven't taken it in yet? Who knows what kind of damage you might be doing driving around like that!

 

Let's see. Coil packs and wires are OK. Spark plugs replaced, fuel pump replaced without improvement. Leaking valve cover found. Pistons and rings are being replaced because they are all fouled with carbon. That would explain all the soot being blown out the exhaust. It's turning out to be a big mess.

 

Sounds like what's happening to my 2007 S auto with 23k miles. Currently at the dealer for past 6 days no. They plan to keep it until at least wed, the 24th. I never got a specific message code, just the yellow check engine light turning on. They said it was the 4th cylinder misfiring due to excessive carbon buildup. I was getting very rough start and idle. I never noticed if soot was coming out my exhaust, but I never checked either. Dealer said they took it apart and cleaned it out and said no other issues, blaming bad gas, which is a lame excuse.

 

Is there any way to view stored trouble codes without using a scanner?

 

no.... Really, anyone with a modern car should just bite the bullet and get a scanner. Get one that does the 4 older interfaces as well as CAN, and get one that can read freeze frame data. This is how you know what the car was doing when the code was thrown (speed, RPM, engine load and odometer reading).

In short, the ECU light is just telling you that the cars brain has something to say. To find out what it wants to tell you, you have to get something that speaks the "language"....

Sure the tools go for $50 to a couple hundred.... But when you think about what cars cost, and what an incorrect repair wastes, it's cheap to get a scanner, and they last a long, long time....

Matt

 

Thanks Matt
That is what I feared. On my '02 vette I can access all the on-board computers from within the car. no special code reader needed. You can scroll through each computer and it will show if there are any Current or Historical codes stored. Then I just look the number up in the factory service manual.

 

Autozone will lend you a scanner for free for 5 minutes to use in the parking lot to read the code. After reading the code you have the option of leaving it for further diagnosis or clearing it.

 

Epilogue: We finally got the MINI back in February after about 2 months. They had to basically remove the head, valves, pistons etc. and send it to a machine shop to clean out all the carbon. The engine basically got a top end rebuild with updated parts.

Luckily Princeton MINI really took care of us and we had a loaner car the entire time and of course everything was covered as a warranty repair. They kept us informed and there was never any blaming "bad fuel" or any other bogus excuses. They just got in touch with MINI and got everything taken care of. They even took care of a few extra service items gratis.

Since then the car has run for another 8,000 miles without problems. I just drained out the old oil and it looks and smells fine.

 

I had the same code and the one saying cylinder running lean after a pulley change. Changed plugs, injectors, different head and cam, coil pack and more. Finally got the bright idea to flow the intake manifold. Shop said 2-3% difference beteween cylinders was acceptable, Cyl 2 was 18-21% more than any other cylinder with stock manifold. My suggestion flow the intake if you have any more problems.

 

is the other three to flow like #2!

But yours is the first case of a bad intake manifold that I've ever run into (I'm sure there are others, it's just very, very rare.)

But after reading over this thread, some other things to keep in mind:

If just one cylinder is reporting misfire, it's going to be something specific to that cylinder, and probably not even the coil! (The Tritec uses something called wasted spark ignition, so there are two coils that fire into two cylinders each and every time they fire... Helps with emissions). This means plug, plug wire, or problems in the cylender in question. For the OP, that was carbon build up in #2.

Anyway, alls well that ends well....

Matt

 

i have the same thing, miss fire on cylinder 4. Dealer has changed coil plugs and injector, with no luck east bay mini has sent in a PUMA to mini usa for more help. i am thinking that it is the carbon build up also,

To me it makes since because we are venting the crank case to the intake manifold and no way to clean the intake with fuel because we are directly injecting fuel to the cylinder.

 

Hello, I have the exact same symptoms with my wife's mini, did you ever figure out what it was?

Thanks,

 

Hello, I have the exact same symptoms with my wife's mini, did you ever figure out what it was?

Thanks,