2003 F150 5.4L P0306

[Zaedock]

Hi guys. I have a 2003 F150 5.4L 92,XXX miles. Had a hurricane yesterday - went for a drive towards the end. Did splash through a couple of puddles, but nothing worse than a rainy day or anything I haven't done before. 20 minutes into the drive, the engine started to skip a bit. Went right home and read a P0306 misfire on #6. I didn't see any water in area, except a couple drops on the harness track. I didn't see any near the COP's or injectors. Pulled #6 COP, and plug (both original). Cleaned, gapped the plug (which looked decent) and COP. Reinstalled - still had a miss. Swapped #6 COP with #1 COP - still had a miss on #6. The #6 injector Ohms @ 14.9. Spec is 11-18. I checked cylinder 1, 2, and 5 and they're all 14.8 to 15.4 ohms (i.e. good).

I plan to replace the plugs this week and am going to order a new COP for #6. The only thing that concerns me is the fact that when I moved the COP, the miss stayed on 6.

Could there be a connector or harness issue? Any ideas?

Thanks guys.


Oh - for those who remember the issues we had with our 04 Malibu Maxx. We're going to trade it in soon for a new family/commuter car. So far, the Hyundai Sonata is looking pretty good. I also like the smaller Elantra with 40 MPG. I'll let you know!

 

[beast3300]

Put digital multi-meter (set on 12v) to the cop plug and see if you get flucuating voltage while it idles. If you do then do the same for the injector. If you get power on both injector plug and cop plug then the injector is bad because the misfire didn't follow the coil pack.

 

[Zaedock]

Cool. I will try that. I was also going to ohm out the suspected COP, but didn't have time as it started to rain again.

 

[440Magnum]

Originally Posted By: Zaedock


Oh - for those who remember the issues we had with our 04 Malibu Maxx. We're going to trade it in soon for a new family/commuter car. So far, the Hyundai Sonata is looking pretty good. I also like the smaller Elantra with 40 MPG. I'll let you know!


I've generally really liked the Hyundais I've had as rentals. But I am seeing a lot about many of the recent Sonatas having a chronic steering pull. Check that out thoroughly before buying would be my only advice.

 

[bdcardinal]

You can always swap injectors. They are the same on all holes on that.

One thing to be aware of is a lot of times those when the injectors go bad they hydrolock the motor.

 

[Zaedock]

Originally Posted By: beast3300
Put digital multi-meter (set on 12v) to the cop plug and see if you get flucuating voltage while it idles. If you do then do the same for the injector. If you get power on both injector plug and cop plug then the injector is bad because the misfire didn't follow the coil pack.


OK! I just checked the #6 COP plug - I have flashing OL with no voltage reading.

I pulled cylinder 1 to compare and get a fluctuating 1.4 to 1.7 connected directly to the connector.

The injector plug has a constant 14.2vDc, just like cylinder 1.

I'm going to check the #6 COP terminal now for corrosion. I may have gotten some water in there.

Thoughts?

Also, thank you VERY much for your help!

 

[Zaedock]

No corrosion. Wires look good.

 

[Zaedock]

Well, did the old fashioned ground the plug. I have spark.

The fuel injector was disco'd though, and I still had fuel shooting out.

I think I have a bad injector.

 

[Zaedock]

Originally Posted By: 440Magnum
Originally Posted By: Zaedock


Oh - for those who remember the issues we had with our 04 Malibu Maxx. We're going to trade it in soon for a new family/commuter car. So far, the Hyundai Sonata is looking pretty good. I also like the smaller Elantra with 40 MPG. I'll let you know!


I've generally really liked the Hyundais I've had as rentals. But I am seeing a lot about many of the recent Sonatas having a chronic steering pull. Check that out thoroughly before buying would be my only advice.


Thanks for the heads up. I thought about the Chrysler 200 too(as I'm a Jeep guy), but frankly, the Hyundai gets much better mileage.

 

[The_Eric]

Originally Posted By: Zaedock
Well, did the old fashioned ground the plug. I have spark.

The fuel injector was disco'd though, and I still had fuel shooting out.

I think I have a bad injector.


Take a long extension (up to your ear) or a mechanic's stethoscope and listen to #6 injector. You should hear the very distinct sound of the injector clacking away. Compare to other cylinders. If you confirmed the injector is stuck, try giving it a good rap with the extension - no [censored]... Wife's car had a stuck injector - found it the same way that I described it to you. Gave it a good solid rap and the car instantly came out of it. This was about 70-80k miles ago. No problems since.

 

[beast3300]

Sounds like injector went bad. You can move it and verify 100% if misfire follows.