Hi, just thought I'd join the forum to help out a friend with a tricky problem.

He has a '98 Ranger 4L that he bought used more than a year ago. The vehicle has a history of burning out the Cylinder 3 spark plug and the service garage keeps getting told by Ford Canada to just put in a copper plug.

This seems to be merely a way of delaying the problem, as it inevitably returns him to the garage with the same problem each time.

BTW, the plug is white when they pull it out. The last visit to the garage polled for errors and found Misfire on Cyl3 and O2 sensor. Rplaced plug and SES went away but returned a few minutes down the road from the garage.

Has anyone else had this problem?

Thanks a lot,
gonzo_guy

 

Hi gonzo, welcome to FTE!

Did your friend replace the wires when he replaced the plugs? If the wires are bad, plugs can burn out in no time.

 

I'm wondering if that one cylinder is running really lean, thus burning hotter. Have the injectors ever been flushed real good (or otherwise serviced)?? All other plugs OK?? Or maybe one or two borderline burned??

 

I would suspect a bad injector on cyl.#3, or it has a vacuum
leak, making it run lean.

Welcome to FTE Gonzo!!

 

I'm going to find out more before I post back. I will check both the spark plug wire as well as the injector - great ideas! Sheesh, didn't know where to start.

Talk 2 U soon,
Gonzo

 

The 4L do have a problem with a gasket causing a vaccum leak, can't recall which one right now.

 

Thanks for all the great ideas! FYI, here's some more details specific to some of the suggestions:
-Spark Plug Wires tested ok
-Injectors flushed
-Vacuum leak was the most thought of possibility. It was tested for compression and a 48 hour moistures test was done. Results were all good.

So, any other ideas? I find it odd that Ford Canada keeps telling the garage to use a copper plug in the 3rd cylinder. It's as if they've had this problem before and haven't solved it, rather, they've found a way of delaying the problem with a plug with a different temperature rating.

TIA,
Gonzo