P0306 Cylinder 6 Misfire Problems

[ShadowedXistence]

CEL came on. Code for cylinder 6 misfire. Replaced spark plugs and light went off after driving for about 20 miles. Then light came back on the next day. Code still reads cylinder 6 misfire. Replaced ignition coil on cylinder 6 (driver's side closest to firewall, is the one I replaced. I read somewhere that this was cylinder 6. Please correct me if I've been misinformed). Light still won't go out. Added SeaFoam fuel injector cleaner to gas tank. Drove it soft and even hard for a little bit. Light still remains. Not sure what to do next. There is no noticeable vibration or stutter in the engine ever. Drives good, accelerates good. Engine still feels as powerful as before.

Not sure how many fuel injectors there are and for that matter which is for cylinder 6. Plan to swap fuel injector(s) off cylinder 6 with another cylinder to see if the code switches to a different cylinder. If so then I know it's the fuel injector. Don't know if I need a fuel injector puller to remove them or if I can do them by hand. Also what lubricant do I need to put the injectors back in.

If this doesn't solve anything, I don't know what the next step is.

Need help! Thanks!

 

[jnaut]

CEL came on. Code for cylinder 6 misfire. Replaced spark plugs and light went off after driving for about 20 miles. Then light came back on the next day. Code still reads cylinder 6 misfire. Replaced ignition coil on cylinder 6 (driver's side closest to firewall, is the one I replaced. I read somewhere that this was cylinder 6. Please correct me if I've been misinformed). Light still won't go out. Added SeaFoam fuel injector cleaner to gas tank. Drove it soft and even hard for a little bit. Light still remains. Not sure what to do next. There is no noticeable vibration or stutter in the engine ever. Drives good, accelerates good. Engine still feels as powerful as before.

Not sure how many fuel injectors there are and for that matter which is for cylinder 6. Plan to swap fuel injector(s) off cylinder 6 with another cylinder to see if the code switches to a different cylinder. If so then I know it's the fuel injector. Don't know if I need a fuel injector puller to remove them or if I can do them by hand. Also what lubricant do I need to put the injectors back in.

If this doesn't solve anything, I don't know what the next step is.

Need help! Thanks!

There is a procedure for making sure your injectors are working. The first one is to use a screwdriver (or automotive stethescope) against the injector housing and you should hear a distinct clicking which tells you it's working. Also, there is a resistance test you can do (requires a meter) to see if the circuit on the injector is good. I don't have the details of this procedure handy... I'll look in my service manual when I get home.

 

[Idaho08KK]

Replaced ignition coil on cylinder 6 (driver's side closest to firewall, is the one I replaced. I read somewhere that this was cylinder 6. Please correct me if I've been misinformed)

You have been misinformed. Cylinder #6 is the rear cylinder on the passenger side.

 

[ridenby]

Good catch IDAHO08KK

 

[ShadowedXistence]

thank you very much for that info idaho! I'll swap that one out and see how things work out for me.

 

[ShadowedXistence]

Just want to say thanks again... this saved me a lot of grief. I took the ignition coil I previously pulled and replaced with new from cylinder 5 since the computer never showed any codes against it, and put that in cylinder 6... reset my light... I've driven it about 50miles so far and the light still hasn't come back on... I'll drive it around some more and see what happens... but just wanted to say thanks for clearing things up for me!

 

[Idaho08KK]

Sweet. I hope it works this time.

 

[Powerslave]

SMPI; Firing Order:
6-5
4-3
2-1

You should have looked it up, and did a few double checks to be sure, would have saved you a lot of time.

 

[Idaho08KK]

You should have looked it up, and did a few double checks to be sure, would have saved you a lot of time.

Well, I'd imagine that's why he asked here.

 

[jnaut]

On curiosity, I note that the OP has a 'jet performance chip'. Is there any evidence that these cause problems due to hotter running, richer/learner mixes... anything?

 

[Powerslave]

Well, I'd imagine that's why he asked here.

Yeah, but he did AFTER he did the wrong cylinder...

 

[ShadowedXistence]

Sure enough... light is back on... hadn't driven it for about a day and a half, slight stutter backing out and went away after pulling forward. Took off on it a little bit, and the light came right back on... Light only seems to want to come on after it has been sitting for a little while. Still need to check the fuel injector, but who knows what's up now.

 

[ShadowedXistence]

fuel injector and housing are good... I don't think it's the o2 sensor. Ignition coil replaced, spark plugs replaced. Don't know what to do... thought of pulling off fuel rail and putting new rings on fuel injectors... Just don't know what to do.

 

[Idaho08KK]

I have replaced a lot of fuel injectors on the earlier KJs to fix misfires. It is kind of a common thing.

 

[Powerslave]

Is it effecting performance, do you get a stutter at acceleration?

 

[ShadowedXistence]

No stutter while driving. Slight stutter in idol for VERY short period of time only when vehicle has been sitting for more than a day.

Checked combustion... Checks out good

solenoid test was good, ohm test on fuel injector was good... there seem to be no problems... just a stupid light, but i would hate for it to get worse before I fix it...

when I pulled the spark plug I noticed the end looks corroded and is green in color... pulled another plug to compare. Other plug is completely normal... Leads me to a fuel problem causing cylinder 6 to run to lean... could be wrong... but I think my best bet is to replace the fuel injector and put in new rings all around...

 

[ShadowedXistence]

Problem solved... replaced fuel injector and new rings all around... drove a little rough for the first 5 miles... now it drives super smooth...

I kept saying earlier that I never felt any stuttering... but now that it's fixed it definately feels smoother...

but anyway fixed one problem and now have another... will post with details

thanks for all your guys' help with the misfire though!

 

[Idaho08KK]

That is what will happen. All of the electrical tests will pass with flying colors, but the injector pintle will not fully seat inside the injector and the injector will have a constant fuel leak into the cylinder and create a misfire.

 

[PunkChachi]

I know that everyone says always use Mopar but it is so expensive. I want to use good parts but am really tight on cash right now. Can I get away with using a different brand and if so what would you all recommend?