P0303 Cylinder 3 Misfire Diagnosis and Repair

hi everyone sue here one auto and i want to talk to you about code po303 and that is a engine misfire in cylinder 3. now this is going to be for any vehicle that has a v6 in it or even a 4-cylinder even a v8 i'm just going to show you how to do a quick diagnostic you can grab a little scan tool if you have one at least to pull the code or you can go to your local garage have them pull the code for you and if you want to look check it out yourself and not pay those fees here's some easy steps to follow [Music] so on this particular v6 we have firing order is one two three in the back so this is cylinder three right here and the car does have a rough running and it shakes quite a bit and the code is po303 so that means cylinder three directly so what i'm first thing i'm going to do is i'm going to take off the ignition coil and that's a direct coil firing ignition so we have this is what they look like if you can't see it in the back now you might have plug wires and you might have just a four cylinder with direct coil or cap and rotor first thing we're going to do is go to that cylinder and see what we find so on this model it has an allen head bolt style that holds it down in i'm just going to put loosen it up i'm going to take that mounting bolt off i'm going to pull this ignition coil right out so we can get to the spark plug as you can see this is the wiring harness there's a clip here just pull on that clip and lift up so once you've pulled the coil you can give it a good check over examine it if you see cracks in the plastic here down in here this is the boot it covers the electrode that goes inside there if you find traces of black soot or white that means that this coil has cracked in its internally so when it's firing it's actually grounding out through the engine block but i don't see anything too obvious visually on this ignition coil so next step to do is let's pull the spark plug so in this car we have a small type spark plug it's just a 5 8 socket with an extension i'm going to bring it down in there bottom it out and i'll just take my ratchet break that free make sure you don't drop it so you see all the black soot and it looks wet right it's got a gloss to it so that tells me that this spark plug is not firing it's trying because it's got a few little spots right here but it's really full of black soot and it's not looking too good i'm going to do something real simple if you don't have compression scanner tools like that so i'm going to swap i'm going to take a coil from the front and a plug from the front and i'm going to swap them i'm going to run this and double check clear the codes first if you can clear the codes then run it and let's see if the skip switches over to a different cylinder and that'll tell us it's either gonna be the coil or the spark plug and if it's either one i'm gonna do both at the same time so now that i took cylinder three apart spark plug and coil i'm going to swap it with cylinder 5 up here in the front right in the middle here so i'm going to transfer the spark plug and this ignition coil over to cylinder 3. we can see the spark plug's nice and clean it's not misfiring so let's see what happens after we swap it so now i'm going to take my scanner and i'm going to clear that code that has po303 on it because i took good known cylinder spark plug and ignition coil and i swapped it over back and forth so then i'm going to run it and the engine's still going to shake because hopefully it's a bad coil or spark plug which is an easy fix but we'll still have a misfire but hopefully it will swap right over to cylinder 4. let's give it a shot so now that you see that we swapped the cylinders three and five and clear the code prior started up and ran it and yep the misfire came right out with a cylinder five so you change all the coils instead of just one because if not you're going to be chasing that around and you want to do the job once do it right and that way you don't have to deal with it you can spend your time with your family and friends so don't forget if you like this video hit subscribe ring that bell turn on all your notifications we'll see you next time