2010 ---137k miles Honda Odyssey--- while driving it today it started running rough and the check engine light came on, flashing… wife drove it home and it got better with only occasional rough riding.

By the time she got home it was running fine, About 15 miles from where it 1st started. I checked the code P0303 Cylinder 3 misfire. I erased the code, added some fuel inject and drove it 30 miles without any rough ride or errors .

Think it is save to keep riding to see if it happens again?

 

welcome to the forum. Might want to check the valve adjustments. cleaning injectors does help, spark plugs and coils also can cause missfire.

 

She took it out for errands today--- will see if it recurs.

If it does, I will get more motivated.

 

I had an exact same problem started back in January after an oil change at the dealer. 1st, the engine light appeared & I had all spark plugs replaced. It disappeared for few weeks and again it reappeared, but this time it was flashing. I replaced, ignition coil for cylinder 3 and again new spark plug for cylinder 3 misfire. The CEL light did go off, but again came back on during hwy driving. I had some mobile mechanic had a look and idiot opened the valve cover & never put it correctly and now it is also leaking oil from the rear valve cover cylinders. I see unburned gas in leaked oil too. It seems like either piston rings are gone bad or foul play in valves. I read in one of the older forums about rocker arm staying open for cylinder 3. I probably have a look by rotating the crank & see if the valves are opening/closing properly. I even had a VCM muzler installed right after the new spark plugs replacement. Current miles are 142K and misfire probably started at 138K. Also, I read somewhere about engine oil cap with carbon deposits if valves have lost adjustments.

 

This post is 7 years old.