how do you know when to change out spark plug wires?i have 53000 miles on my f150 4.6 and seems to be less responsive than before.what would be an average mileage we could expect to get out of the factory wires? also best brand to replace with. i tried doing a search on this but the search function is disabled. thanks again!

 

You might be just wasting money by replacing the wires. I have 63000 miles on mine and original wires. I used to do that in the old days, replace wires often and I never did notice a difference in performance. I think these trucks are a pain in the *** to change plug wires so I wouldn't rush in to it. I really don't think that they go bad that often.

 

Mine lasted fine until almost 110,00 miles, but it differs from truck to truck. They are a pain to change. Don't think it will improve anything unless you are having a major problem with them.

 

I had the originals in mine until 112,000 miles or so. Changed plugs and wires, and there was little difference in the before and after. If they aren't giving you problems, then don't bother.

 

When they do need to be replaced, how did you know? Did you just feel a slight miss or did you notice poor gas milage or what?

 

the mechanic told me replacing the wires is a waste of money unless they have been cut or burned through and are shorting he said that most aftermarket wires are poor quality you should go with factory wires if they do get damaged.

 

I replaced mine at 98,000 miles or so with Bosch plug wires and Plugs I think they help perormance slightly, and it was a pain.

 

To answer your question, you replace your wires when the measured resistance, from end to end, is greater than 2000 ohms per foot of wire. Use your DMM, set to Ohms, and measure each wire. The mechanic who said "replacing the wires is a waste of money unless they have been cut or burned through and are shorting" should be in another profession. There are many reasons a wire can fail, or at least not be able to do it's job properly.

Inspect them visually, then measure their resistance.

Take care,
-Chris

 

i would wait as long as possible or let the Ford place do it, i changed my spark plugs saturday, not intending to change the wires, but the only way to get the #4 wire out was to rip it and eventually it ripped off.......so i had to buy new ones....and for all that, i didnt get a bit of performance help, even though my old factory plugs with 80,000 miles were gapped at .065-.070....figured it would help out a lot but no nono....shoulda waited a while in hindsight

 

You may want to try running some fuel injector cleaner through it. I did that to my wife's 98 Taurus 3.0 DOHC for the first time at 48K and it made a considerable difference in performance. Car is fed Shell regular mostly.

 

you need to change wires are the first time you change the plugs. The stock plug wires will not stay on the plugs and they will pop off. The only solution I have found so far for the 4.6 is new wires. As soon as you get new wires, all problems are solved.

 

STX/98, I fouled a plug out and I had a really bad misfire in my number 3 cylinder. Truck was running, but it shuddered so bad it was hard to hold it in the road, sometimes at highway speeds, it would be okay, but 90% of the time, it wasn't worth a sh**, so I changed plugs and wires, because my wires just looked old. If in doubt and you can afford it, go ahead and change the plugs and the wires, it's worth doing anyway, can never hurt to have a new set. Good luck!

 

Guys I took the advice and measured my stock wires....They are perfect and milage is 120,569 Truck runs like a top and only changed plugs once @ 80,000 miles, and what a pain that was....

 

I have a 1998 4.6L with 70,000 kilometers on it. Brought it over for service last night to have them check the computer because my truck spuddered and check eng. light came on. They said it was a misfire on #5... They said I need to change my plugs and wires. How do you guys get 100,000 MILES and I can't get 100,000 KILOMETERS?????

If I have to change plugs and wires which do you recommend?

Thanks for any help...

 

OEM.

Take care,
-Chris