Simple Fix for a P0303 Engine Code - Cylinder 3 Misfire 2009 Honda Odyssey 

The problem is the VCM, Variable Cyclinder Management. The engine shuts down 1 to 3 of those rear cylinders as the car is driving as a means to increase the MPG numbers. Since they don't have constant spark, the plugs get fouled, the cylinders burn oil and the coils fail prematurely. #3 is always the worst because it's the cylinder programmed to shut off first and the most.

How did we miss this! Awesome video and thank you for sharing.

Nice camera work! Good explanations and critical thinking. Way better than most! Thank you.

We used to get our maintenance done by the Honda Dealership. After they tried to charge us nearly $10k for 'repairs' related to this issue on our 2016 Honda Odyssey with ~60k miles, we said no thank you. I changed the spark plugs and installed a VCM Tuner 2 module to disable VCM function. Running fine now.

I have a 2011 honda odyssey. I get cylinder one miss fire and sometimes cylinder 4 misfire, I replaced all 6 coil packs that did not fix it. I replaced all six plugs and it fixed it. But after 1 to 2 months it misfires on number 1 cylinder I put new plug in cylinder 1 and it fixed it. Keeps fouling out the plug very oily and dirty. I was told it may need valve job on that cylinder one and 4. Could that be the issue I'm having. And how much would that cost for a valve job if that's the problem. Any help would be appreciated. Thank you.

Simple and cost effective is always good even when you factor in the ridiculous cost of spark plugs, not much better on the other side of the pond, keep the vids coming

And what caused all the oil on plug? The VCM system on these Honda's. Car can't missfire unless running.

I had my sparkplugs replaced 50k miles ago. Im thinking it could be my fuel injector as i smell gas and car rough idles a lot and slow to accelerate

I have the same 2009 Honda Odyssey EXL. Just turned 150K. I'm going to subscribe not just because that but I fix small engines as a side hustle. Looking forward to exploring your channel. K Paul from Connecticut

Very helpful. May I ask what your mileage is on your van?

Wish I could send a picture of what the plug looks like on here.

Also the valves may need adjusted

Install a s-vcm device on that engine. Disabling vcm.will extend the life of that engine.

Instead of doing the parts, cleaning, swapping deal and the parts canon swapping why don’t you get you a 0 meter measure the resistance on the plug and you should’ve measured the signal on the coils, looked at your graphics scale on the misfires on the scanner see if it had voltage or go to data and look at the coils datainstead of playing a guessing game, diagnosed the problem and the intake is not that hard to pull less than five minutes you spent more time fighting to get the coil out

Hopefully the spark plug.on cylinder number 3 is cracked causing it to ground out

I want your help please I have the same problem and the same car

VCM to blame. MIsfire will return as some point,

Those Jay motors three fives. They’re real simple to work on the intakes not hard to pull at all. I don’t know what’s wrong with people anymore. They don’t want to do no diagnostic no more they don’t want to do shit just swap parts at it load of shotgun. he was already there could’ve done a compression test put a vacuum gauge on it. Throw a little bit of carburetor cleaner at it. See if you got a vacuum leak. See if you got a dead injector vacuum gage will tell you if you got bowel problems from what I can see, you got a code reader

S vcm delete ...easy installation fixes everything

Have 2007 ODDESSAY TWO COILS BAD SO REPLACED ALL SIX , IF ONE BAD OTHERS RIGHT BEHIND ! 160 THOU MILES REPLACED WATER PUMP AND TIME BELT EVEN THOU RUNNING FINE , OLD BELT DRY AND BRITTLE AND HAD CRACKS READY TO BREAK ! IF DID NOT REPLACE THEN SEVERE ENGINE DAMAGE CAN OCCUR ! SO CAUGHT BEFORE DISASTER ! HEADS UP ON THAT !

Bypass that vcm