Misfire on highway at cruise and light acceleration

[jwallask]

Help!

Saw a similar post but no resolution.....

I have the same issue, verbatim!

2007 Eddie Bauer Explorer 4.6L - 8Cyl

Changed out the fuel filter already.....

Any help would be appreciated.

-John

 

[Explorer_PL]

Hi Jwallask

Read all the posts, there are probably 50 of them by now. I had similar issue on my 06 v8, and new coils and sparkplugs fixed it.

It seems that that covers 80% of the cases.

 

[Ornery]

If you're still on original plugs, what the hell? Replace them! That's routine maintenance, so no wasted time or money in that endeavor. If it's still acting up after that, pull the code. Narrow it down to one cylinder, so you're not just throwing money at it.

 

[jwallask]

Thanks, guys.
I did a search and came up with about a dozen hits regarding this issue. Probable causes and resolutions were all over the board...
As for the spark plug comment, Ford's first maintenance callout to replace is at 100K and I'm around 90 now....

 

[polizi212]

Thanks, guys.
I did a search and came up with about a dozen hits regarding this issue. Probable causes and resolutions were all over the board...
As for the spark plug comment, Ford's first maintenance callout to replace is at 100K and I'm around 90 now....

Unfortunately Ford sometimes forgets to tell their parts that they are supposed to last till 100K miles. So replacing them early wont hurt one bit!

Since it appears that your issue is not easily narrowed down by looking at other posts, you are going to have to do this by the process of elimination till you figure out what fixes this!

 

[Ornery]

You kids are spoiled! The first cars I owned needed a "tune-up" EVERY YEAR! That's new plugs, points and condenser every 12 months. New wires and cap every couple years. Oil change every 2,000 miles, and I believe 7,000 miles was considered a year's worth of driving. In many ways, I don't miss "the old days".

I wasn't always a Ford guy!​

Pic taken at one of my first jobs, where we got paid to pump gas for people.​

 

[Flag Gibby]

I hear you Ornery, my family owned a fuel/repair shop way back in the day and I was made aware of full engine overhauls (by my father that he performed) at 50000 miles or less back in the day too. Thanks to modern engine oil formulations, they have helped engines out tremendously in terms of lifetimes.

Back to the O.P., just because you are not at the recommended change interval does not mean that you are not having issues with your plugs. There were major issues with the plug setup on the 4.6L V8's until about mid 2008 when they modified the engine design and fixed the manifold and pooling water in the spark plug wells. Personally, I believe that if you get 60,000 miles out of the plugs then you got a good amount of life out of them and it is time to replace them. Remember, as plugs age the gap increases on them and at some point is too great to always fire correctly so unless you are pulling the plugs and resetting the gap say halfway through the lifetime of the plug then you will start having minor ignition issues at some point because there will not be enough voltage to always jump the gap on the plug.

 

[thebrakeman]

Original poster,
If you read all of those posts, you must have read by now that the longer you wait to change those plugs, the more carbon will have built up around that sleeve, and the greater risk of the plugs breaking on removal. I agree...change them ASAP.

But while someone said change the plugs, then have scanned if needed...
I would recommend scanning first, to see where the problem is now. If it's a misfire on cylinder "X", it would be nice to have confirmation after you change the plugs that the misfire is gone (more than just you not feeling it anymore).

Most autoparts shops will run the scan for free.