2008 Ford Explorer misfire.
I have a 2008 explorer with a 4.0. I recently purchased it for my daughters college car. I knew it need some work but didn't expect to struggle to fix like I have.
Misfire codes P0306
Replaced the following:
I'm at a loss and have thrown enough parts at this thing.
Thanks in advance for the help!!
Did you clear the code after replacing all those parts?
Yes. Cleared all the codes. Before replacing the ECM.
Have you looked at fuel delivery? Fuel psi? Injector on cylinder 6? Leak down on cylinder 6? Compression on #6?
Definitely check the compression before throwing more parts at it.
Yes. Thanks for reminding me. Also replaced #6 injector, compression and leak down test. Also checked all wiring back to the ECM
Fuel delivery seems fine. Checked injector spray when I had the rail off.
I have Spark, Fuel, and Air. I'm at a loss....
You could try swapping out parts to see if the trouble stays at #6 or moves with the part.
I know this probably has nothing new for you but if it helps you then great ------ https://www.yourmechanic.com/article/p0306-obd-ii- trouble-code-cylinder-6-misfire-detected-by-jay-safford
Any vacuum lines or pcv close to this cylinder? We're all your psi readings in spec? Borderline can cause issues. Any arcing inside plug well on #6?
Did you put on a new O-ring on new injector? All of them? You could be losing psi on dry O-rings
Buying a device that hooks up to the OBD2 port that gives you live data might be the next step. Something like this ----- http://www.auterraweb.com/
To further explain. The misfire code PO306 was stored, the engine light is on at idle, and while driving the engine light flashes. It has a rough idle and extremely rough in OD at highway speeds.
Flashing light is bad. It means that you are in jeopardy of ruining your catalytic converters if driven like this. Raw fuel getting down that far without being burned. Yes buy a live data scanner to monitor different systems. Harbor freight has a cheap one but autel is a good brand. I have 2 autels and a harbor freight one. Any O2 sensor codes?
Live data device it is. I will get one ordered. What exactly should I look for as far as data? Thanks F_O_R & Guru9FSV8. If y'all think of anything else please let me know.
It had no lean codes or O2 codes. Just Random misfire P0300 and #6 P03006
Any thoughts on it being an issue with the crankshaft sensor?
P300 is almost always fuel related! Look at short term and long term fuel trims and oxygen sensor activity with engine at operating temp. There are a lot of good YouTube videos on how to read live data and misfires. Wells automotive has good ones
Almost sounds like a good sized vacuum leak causing you ECM to overcompensate and pour in the fuel...hence the flashing check engine light and unburned fuel getting downstream.
Could be.... AC is stuck in defrost mode. Vacuum controlled I think.
Using fuel trims to determine type of misfire by scanner danner on YouTube is a good video. I want to say gasket leak. You said you replaced manifold gasket. Are you sure it sealed? Fel Pro gaskets are good. This goes along with vacuum leak like I said earlier
Ill check it out. Yep, I even pulled the intake back off to verify. Everything looks good. When I get the live data scanner hopefully some questions will be answered.
A flashing light on Fords means that a code is pending at least on the two I own. I would look at fuel trims like others have already mentioned. One possible source of a hidden vacuum leak may be behind the battery box. On my Fords the vacuum tank is on the back side of the battery box next the the fender and on my F150 the vacuum hose rotted off at the tank which is totally hidden from view.
Oh man, I have exact same symptoms but on cylinder 2. Replaced spark plug, spark plug wire, gnition coil pack and fuel injector. Mechanic thinks it's pcm. He said he checked wires from pcm to fuel injector. He said he ran multimeter on fuel injector leads and could see it losing signal periodically. Did you ever get yours fixed???
Also, mine is 2008 as well...
Also, mine is 2008 as well...
No reply... Please...??
Yes. After throwing a bunch of parts at it I finally figured it out. That was two years ago and she has been driving it ever since with no issues. It turned out to be a broken valve spring. $5.00 part
May God shine kindly on you, sir! I pray that's the same for me... I'll find out this weekend? Was it difficult to change out? I've never been that deep in an engine before. Plenty of YouTube vids though...
For others experiencing similar issues... I did and do not have a broken valve spring. I did find the connecting wires to my EGR had a spot where all the wires sheathing was worn off and those wires were touching. I fixed that. I replaced my EGR and cleaned my intake. While doing this work my battery cable was disconnected. I drove many problem free miles over the next couple of days. However, slowly but surely the problem re-arose. Its very odd. It makes me think it's something electronic.
Or possibly vacuum hose related