Hi everyone! Have a 2009 Honda Accord EX with a 2.4L Engine. Was driving home and engine lost power. Could only drive about 30MPH unless I hit a downhill slope. OBD2 code is 301. Did the usual. New spark plugs. Swapped plug coils to see if it changes the code to another cylinder. The 301 still persists.

Did notice while changing plugs that the one on cylinder 1 was black and gummy. Checked the fuel injectors they all work good. My first thought was that one of the coils were bad, but when swapping the coils, the OBD2 code is always 301(cylinder 1 misfire). Also, I can clear the code and start the engine with all four cylinders firing. After about 30-60 seconds the engine light comes on and then i can hear a noticeable change in the engine. Cylinder 1 stops firing again.

Not getting any other OBD2 codes. Any ideas what to look for next?

 

Got a new plug coil today. Still no change. Not sure what's going on. For about 30-40 seconds when starting the car everything sounds normal. After that, engine light comes on and a noticeable change occurs right when the light comes on. Starts misfiring.

 

Starting to wonder what sensors or if the computer is borked. Would think that a sensor would show up in the OBD2 codes but I am only getting the 301.

 

 

How did you check the fuel injectors? My next step would be to swap injectors between cylinder 1 and another cylinder. See if the CEL indicates cylinder 1 or moves to the other cylinder.

 

Yep, tried swapping the injectors. I actually used a little trick with some different size tubing, carb cleaner and a battery to make sure they are spraying evenly. However, whenever I pull the sparkplug out it is wet. When I, clear the engine code, start the car, it runs normal. 30-40 seconds later, it's like the spark just quits. I have 4 new spark plugs and a new coil on cylinder 1. This seems to me that it is a computer problem, because the result is exactly the same every time. When I replaced the plugs, cylinder one was black and gummy.

There was a piston ring recall and when I received it I had 160000 miles on the car. The recall was only good up to 125000, so never did it. I now have 241000 miles, so this car really doesn't owe me anything.

I believe that oil is leaking into the gas chamber and is the root cause. I have gotten by this long by using an oil addative called Restore. It works and actually increased compression on the cylinders. Honestly, this car has run better than any car I have ever owned. Was just hoping to squeeze some more life.

 

I doubt oil leaking into the cylinder would cause your issue. You should do a wet & dry compression test.

There are a few more simple tests you can try, because it may be a wiring or PCM problem.. Unplug the electrical connector to the injector. One of the 2 wires to each injector will have the same color on all 4 injectors. The common color wire will have 12V to a good ground with the key in the II position. The other wire should be an open circuit to ground, until the engine computer grounds that wire to open the injector.

 

Honestly don't think it is an injector. Why would the plug in cylinder one always come out wet? It's either spark or oxygen. Not sure what needs to be checked for oxygen. Don't have the tools to do a compression check. I actually also took all of the injectors out and intermittently supplied the 12v to each one while running some carb cleaner through them. All of them were working fine. Cylinder 1 works for a short time when I clear the engine code. And then it stops firing. Is the plug getting wet from a lack of spark or a lack of oxygen? That's what I need to figure out.

I did temporarily remove the air filter and to my surprise the engine smoothed out and stopped running rough. Probably need a new one. That does not prevent the code from reappearing though. I would have been mortified if that's all it was.

I have an Actron pocket scanner and I am confused that the code is alway 301(cylinder 1). Have swapped spark plugs, coils and injectors. The code is alway specific to cylinder 1. Does this pocket scanner only show a 301 even if another cylinder is the cause? Did the parts store sell me a dud coil? If I didn't have to work all day, I might have time to figure some of this stuff out. One way or another I'll will have this thing fixed or be driving a new car by Friday. Go on vacation on saturday and I'm not missing that.

 

If the injector is sticking open, or somehow leaking too much fuel, it could be too rich to ignite. That'll cause the wet plug as well as the misfire code.

Try a new plug. One time I had a flooding problem & after I fixed it the engine still wouldn't fire. The plugs looked good so I was too stubborn to replace them. When I did, it worked fine. So it's possible to have a fouled plug that LOOKS just fine.

 

Could be wiring though. Or PCM.