Do these autolite double plats need replacement?

Messages
2,696
Location
San Rafael, CA
Ford 4.2, rough idle, no misfires, no codes. Runs fine at higher rpm. Gap was almost exactly the spec of 0.054.

1609195749363.jpg
 
Messages
2,105
Location
Cincinnati, USA
In most of the world no, but in the land of plenty you might as well replace them while you have them out. Small cost, delays when you'll need to replace them later.

You can hook the plug wire up, touch them to any ground, and see if they're sparking. I'd imagine they're fine since you aren't getting a particular one missing enough to get a misfire code.

I'd hook up a scan tool capable of live data and look at that including long term fuel trim, check air filter, clean MAF if present, check fuel pressure, and so on. If it has an IAC valve it could be about due for that to be cleaned or replaced, or throttle body cleaned.
 
Messages
1,139
Location
Pacific Northwest
I would replace them, electrode is rounded and looks eroded in your pic. This may not be the source of your poor idle, though. One common issue with the 4.2l Fords is that the intake manifold develops vacuum leaks, especially when the rubber grommets that seal the bolts go bad.
 
Messages
2,815
Location
Kentucky
The white deposits on the electrode and tip might be indicative of a lean condition or ignition timing too advanced. Hard to tell from the photo though.

Given the roundness of the electrode, they've got plenty of miles on them; I'd replace them.
 
Messages
994
Location
PR CA, USA
For the cost of spark plugs and considering you took the time to take at least one out, replace them. And use any brand but autolite according to my mechanic.
Autolite work fine in older Ford trucks. True that now you have one out and are worried. Just change them and have one less thing to stress over.
 
Messages
2,815
Location
Kentucky
Why do folks hate on Autolites and non-OEM plugs so much? It's a spark plug for crying out loud, not a flux capacitor.

As long as you're not using one of those gimmicky plugs like the +4, E3, etc., the aftermarket plugs should work just fine provided you use the same style as OEM (e.g. iridium, 2X plat, etc.)
 
Messages
1,240
Location
Vancouver
Why do folks hate on Autolites and non-OEM plugs so much? It's a spark plug for crying out loud, not a flux capacitor.

As long as you're not using one of those gimmicky plugs like the +4, E3, etc., the aftermarket plugs should work just fine provided you use the same style as OEM (e.g. iridium, 2X plat, etc.)

I used to use them a lot in the 90s but they definitely have more bad ones out of the box than any other brand I have tried. Mind you it has been about twenty years since I have purchased anything other than NGK. The last straw was three bad plugs out of eight, and I'm not exaggerating... It was bad.
 

dogememe

Thread starter
Messages
2,696
Location
San Rafael, CA
Thanks all I did replace this one which was on cyl3 because I had a p0303. it makes sense this one doesn't look happy because the intake manifold runner control system on this bank was not working. i've fixed that in the mean time.

I will replace the rest of them with motorcraft since i used motorcraft in cylinder 3. I didn't do any gapping - just took this one out and put the motorcraft in.

Have new wires too so hopefully all that makes a difference.

throttle body has been cleaned. fuel trims are decent.
 
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