1999 Explorer 5 liter. Driving the other day down the hwy there was a miss at neutral throttle, no codes. It has been getting worse the past few days and yesterday it had a code. "#7 cylinder misfire". I haven't looked yet, any ideas?
Thanks

 

When was the last time the spark plugs and spark plug wires were replaced? Start with the logical stuff, and the stuff that would be considered standard maintenance anyway in the event you don't find something obvious.

-Rod

 

Good advice above. Cover the basics first.

I just did plugs and wires on my 5.0 Mountaineer this weekend. Two of the wires had chafed through the silicone jacket. The boot on cylinder 7 was brittle to the point where it just fell apart when I tried to remove it. The wires that were on there didn't have the heat shields that the Motorcraft wires had. Although the plugs that were installed were iridium, two of them were missing the iridium. Surprisingly, there were no obvious drivability issues, although it does seem to run a bit better. Could just be the placebo effect.

No matter what kind of plugs and wires you install, I don't think it's a good idea to leave them on that long. It appears as though the 5.0 is hard on them.

Make sure to route the wires away from the exhaust manifold and clock the boots for good clearance from the manifolds.

 

Thank guys. I did check #7 plug and broke the wire pulling it off the plug. The plug was shot and Ford discontinued the plug wires so I bought a replacement, installed them and cleared the code. All is good but I'm going to replace the rest of the plugs and install new wires.

 

Congratulations! Thank you for the follow up post.

-Rod