Bought this Fit (07 Base) use with 100,000 mi. Only put 6,000mi on it.
I will be putting in new coils (Hitachi OE Part).
I happened to remove a plug to examine it, it looks good but is a Denso PK20TT.
What have I got here?
I looked this plug up at Rock Auto and it is Iridum, what is the difference in the two?

Manual calls for NGK IZFR6K-13, or Denso SKJ20DR-M13

 

With plugs always stay with the OE part, wherever you decide to buy it. Cars' machine spirits can be very picky about spark plugs.

I'd lean towards the NGK, but if they're listing that Denso in the manual then feel free. The difference between them and anything else is that nothing else is a specifically listed part number.

"Better" or "worse" doesn't mean a thing with plugs; not specified means everything.

 

Yes, you are right, go with the specified.

 

Iridium spark plugs often come pre-gapped due to the fragile little electrodes they have. I know the OEM NGK ones do...

I didn't see any mention of the as-delivered gap on Rock Auto, but they DID link to a write-up from Denso on how to gap and install Iridium plugs.

Installation Guide: DENSO Iridium

Did you check to verify that the plugs hadn't loosened before you removed them? (This has been a cause of misfires)


IMO you could verify the correct gap and reinstall them when you replace the coils.


Are you planning to check your valve clearances?

 

Not messing around, replacing plugs as well as the coils. Using OE parts.

Valve adjustment 6,000mi ago.

 

I would replace the plugs with NGK since they are due. Why wait, stuff usually breaks at the worst possible time!

 

I am doing just that!