Bad misfire and P0306 code

[Seb]

Immediately after driving the car on the highway for an hour today it started to misfire badly. While stationary at the first traffic light at the top of the off-ramp, CEL started flashing while the rpm’s were dropping, and car sounding like a Harley two stroke. I managed to nurse it 500 yards into the first safe spithere it stalled.

My OBDII reader returns code P306 (cylinder 6 misfire). I didn’t turn on the engine again. Waiting for the tow truck now.

Oil temp and pressure looked healthy judging by the dials in the dash.

I’m crossing my fingers it’s a bad spark plug or coil pack.

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[NGOT8R]

I just had the exact same thing happen to me recently (check engine light flashing intermittently and running rough), following a new clutch install. P0300, 0303, 0304, and 0307. I was about 20 miles from home and just drove it easy. Once I made it home, I did a crank relearn and it’s been running smooth ever since.

 

[NGOT8R]

If you don’t have far to go, you can likely save yourself a tow bill (unless it’s free with roadside assistance) and drive it home.

 

[Cobra Jet]

Swap #6 coil pack with #7 and see if the code followed; if it does it was a bad coil pack. Also check all engine harness connectors and make sure all are secured (not loose).

 

[Seb]

If you don’t have far to go, you can likely save yourself a tow bill (unless it’s free with roadside assistance) and drive it home.

I’m an hour from home so don’t want to risk it…

 

[Seb]

I just had the exact same thing happen to me recently (check engine light flashing intermittently and running rough), following a new clutch install. P0300, 0303, 0304, and 0307. I was about 20 miles from home and just drove it easy. Once I made it home, I did a crank relearn and it’s been running smooth ever since.

Still on the original clutch and the last service was an oil change at 7.5k miles. Odometer is at 12k miles now.

 

[NGOT8R]

Sometimes these cars just do weird stuff. I‘d never had that problem surface before my clutch install. Please let us know what you find once you’ve had a chance to investigate the cause.

 

[honeybadger]

look closely at the wires for both the injector and coil pack and see if you can see any signs of stress. Alternatively, you can try moving the wires around to different positions while the car is running and see if it fixes the misfire.

 

[Seb]

4 hours later

 

[Rapid GT350R]

Curious how this goes. Ever do the cam chain tensioner check to see if yours was activated?

 

[Seb]

Curious how this goes. Ever do the cam chain tensioner check to see if yours was activated?

Yes I did when the TSB came out and they were fine.

 

[cortez]

I just replaced my clutch/flywheel, and passenger side Cat converter, and the CEL light is lit with DTC codes P0300 and P0301. There were a couple of days in between the CEL light being on where the CEL light went off, and there were no DTC codes reported. On the following day the CEL light began flashing and finally stayed lit and reported the same DTC codes. Troubleshooting steps followed by the dealer:

1. Compression test - PASSED
2. Check Cylinder 1 for oil leak - no leak, PASSED
3. Swap Coil from Cylinder 2 to Cylinder 1 - Cylinder 1 still reports misfire
4. Swap plug from Cylinder 2 to Cylinder 1 - Cylinder 1 still reports misfire

The engine idles fine and there is no shuddering or sluggishness when I drive the car. My car is still under warranty, and I'm going to request they replace the plugs and the coil in cylinder one to see if that fixes the issue. Any other troubleshooting suggestions would be appreciated.

 

[honeybadger]

I just replaced my clutch/flywheel, and passenger side Cat converter, and the CEL light is lit with DTC codes P0300 and P0301. There were a couple of days in between the CEL light being on where the CEL light went off, and there were no DTC codes reported. On the following day the CEL light began flashing and finally stayed lit and reported the same DTC codes. Troubleshooting steps followed by the dealer:

1. Compression test - PASSED
2. Check Cylinder 1 for oil leak - no leak, PASSED
3. Swap Coil from Cylinder 2 to Cylinder 1 - Cylinder 1 still reports misfire
4. Swap plug from Cylinder 2 to Cylinder 1 - Cylinder 1 still reports misfire

The engine idles fine and there is no shuddering or sluggishness when I drive the car. My car is still under warranty, and I'm going to request they replace the plugs and the coil in cylinder one to see if that fixes the issue. Any other troubleshooting suggestions would be appreciated.

probably a wiring issue. continuity test on the harness would tell ya. If under warranty, push for a new harness.

 

[Bluelightning]

I just replaced my clutch/flywheel, and passenger side Cat converter, and the CEL light is lit with DTC codes P0300 and P0301. There were a couple of days in between the CEL light being on where the CEL light went off, and there were no DTC codes reported. On the following day the CEL light began flashing and finally stayed lit and reported the same DTC codes. Troubleshooting steps followed by the dealer:

1. Compression test - PASSED
2. Check Cylinder 1 for oil leak - no leak, PASSED
3. Swap Coil from Cylinder 2 to Cylinder 1 - Cylinder 1 still reports misfire
4. Swap plug from Cylinder 2 to Cylinder 1 - Cylinder 1 still reports misfire

The engine idles fine and there is no shuddering or sluggishness when I drive the car. My car is still under warranty, and I'm going to request they replace the plugs and the coil in cylinder one to see if that fixes the issue. Any other troubleshooting suggestions would be appreciated.

Did you do a crank relearn after you changed the clutch?

 

[cortez]

Did you do a crank relearn after you changed the clutch?

first, let me clarify that the dealership replaced the clutch. i'm waiting for the dealership to confirm they performed the crank relearn procedure.

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