Change my Spark Plugs, take a look

About 101K miles and never been changed before. Was a pretty easy job. I'm attaching a picture of the old plugs. Truck ran awesome but I could detect a very minor rough(ish) idle. Replaced with the same exact Denso Iridiums (Part #3421) and the truck runs good, the idle is now smoother than silk! However, the really nice "VROOM" I would get on startup is no longer present (I have a TRD Dual Exhaust and TRD Intake). It starts quieter. I would appreciate an explanation why. In addition, while the truck runs like a top, I almost feel like power is down a bit from where it was. I know this sounds crazy. I put the new plugs in right out of the box - no adjusting the gap, could that be why? Pic of old plugs attached, any observations as to condition are welcome. Thank you.

 

If the gap wasn't checked then then it certainly could be an issue. If gap is too small there is less spark than there should be.

The old plugs look to be well used and normal for the milage.

 

The plugs look pretty good. Drive the truck around a bit and let it relearn some things; could just be relearning some ignition timing.

I just changed out my (suspected) counterfeit plugs after only 60k miles or so on them. I had a slight miss at idle and found one electrode to be completely burnt. The truck is quieter and runs smoother, especially at idle. For a few days it kinda felt a little down on power - barely - it that has since disappeared and feels like it should, power wise. It runs better throughout the powerband so I think perhaps it was just my perception and needing to apply a little more throttle on the get go before changing plugs, making it feel more powerful.

 

From what I’ve heard / read, you’ll break the iridium tip if you attempt to adjust the plug gap on these. They should have come pre-gapped.

 

these look like they got hot. Probably lean.