2002 Ranger XLT, Extended cab flareside, 4.0 L, SOHC, 5-speed manual, approx. 121,000 miles.
Per what I've found here, appears correct replacement spark plug is AGSF34FP double platinum. Original plugs still running okay, but thought I'd replace so I purchased new plugs, gapped them and applied light coating of anti-seize to threads.
Since I'm of an advanced age, I seldom do much mechanical work any more, so mentioned to my mechanic that I'd like for him to change the spark plugs in the near future, and verified that he was familiar with the correct procedures.
Not only was he familiar with the procedures, but he informed me that gapping the platinum plugs could potentially "scar" them and possibly induce a misfire after installation.
Did I screw up when I gapped them? To be on the safe side should I re-purchase and omit gapping?
Thanks in advance.
Thumper

 

I've always gapped platinum plugs and have never had a misfire. I'd use them.

 

Kinda depends on what gap tool & technique you used to perform the gap set. Maybe review the thoughts in this mini spark plug tutorial https://www.ford-trucks.com/forums/1...-tutorial.html, about gapping & the latest spark plug design benefits we might experience.
If you didn't force the gap gauge through too tight a gap, your likely ok. If unsure, remove an easy to get at plug & inspect the pads under magnification to see if they're damaged.
Since you used a dab of anti-seize on the plug threads, hope you also compensated for the lube effect by setting your torque wrench to the plugs min torque spec, so as not to over tighten the plugs & maybe mess with the spark gap.
Sounds like your Tech is up to date on best practice procedure details & that's refreshing to hear.
Some thoughts for consideration.

 

Thank you to Bruker and PawPaw for their replies!
From the additional research I've done I have pretty much decided to do same as PawPaw's advice: Look at the center electrode and the area of side electrode directly across from it under magnification and ascertain whether I marred the platinum coating thereon when I gapped the plugs. If I feel comfortable with their condition after inspection, then I will try using them. Probably start engine and check for misfire before re-installing the inner fender well..... :-)

PawPaw, I have always been a bit fanatical about always using anti-seize between ferrous based metals and aluminum. Ever since I blew the spark plug completely out of the head on that 1959 Alpha Romeo Spyder due to corrosion caused by non-similar metals many years ago.... :-) I generally yank the plugs out of anything I purchase, even brand new, and apply anti-seize to the threads, if it has an aluminum head; but when I bought this Ranger, the necessary procedure was such a pain in the butt that I omitted doing so. I'm quite certain my laziness in the matter is gonna bite me in the butt when we go to pull the old plugs since it's got 121,000 miles on it now and they've never been out. :-(
Thanks again, All, for your kind replies.

 

Depending on the plug mfgr you used, they may already have anti-seize compound applied, or a anti-seize coating / plating applied, so no real need for us to add additional.
I've always added a small dab of anti-seize after my 78 Merc Zypher iron head I6 #6 Motorcraft factory spark plug came out but with protest. It came out ok, just with considerable protest & I took the hint, cleaned the head & plug threads & added a Small dab of Permatex/Loctite high temp nickel anti-seize & no problems afterward, so I've continued with the practice since, on my aluminum & iron head engines, with positive results.

Since you want to inspect your work, I take it that you might have tugged on your gap tool on some fairly tight gaps & if you were using a flat type feeler gauge, its square edge might have skived off the welded on thin platinum wafer. If you used the latest design Fine Wire iridium enhanced center electrode type plug, inspect it closely too, as we can damage it when using the wrong gap gauge, to prying the side-wire to reset the gap. A wire type feeler gauge is safer as its rounded, so not as likely to skive off a platinum pad, or damage a fine wire center electrode.

If you decide to replace the plugs, consider the fine wire center electrode design, as I've found they make for a positive result in quicker starting year round & their spark gap is staying in spec Way longer for me.
More thoughts for consideration, let us know what you find & decide to do.

 

Perform the voltage tests to & across the switch & if ok, disconnect the switch electrical connector & measure the resistance from the connector ground lead to a good clean, non rusty, non painted or greasy body & then engine ground, then to the battery B- cable clamp, then to the battery post. As the manual suggests the resistance should be less than 5 ohms & I'll add wiggle the connections while measuring, as a loose ground connection between the battery B- post & the engine, or body can confuse the ABS module. So make sure the switch ground lead & its ground connection is clean, bright & tight & the same for the body to battery ground connections as mentioned above, so wiggle those connections while measuring resistance & make sure they aren't above the 5 ohm Max the service manual calls out.
Same for the B+ feed to & across the switch. The breakout box is just a convenient way to make test connections, but we can sort of rough it on the test if we don't have access to a breakout box, or don't want to take the time to construct it for a one time in a blue moon test.
Btw what color is the master cylinder switch electrical insulator???
Make sure wheel bearing play is in spec, as excessive bearing wobble can mess with the generated ABS sensor voltage, as it'll affect its distance between the sensor & tone ring. The sensor needs to be held firmly in place & no deposits on the sensor, or tone ring & the tone ring needs all of its teeth.
Some thoughts for consideration, let us know what you find.