NGk iridium 9 6619

Precious metals plugs such as Irridiums are not supposed to be manually gapped. The coating of precious metal on the electorodes is super thin and manually gapping them can harm the coatings.

1GR was designed for regular plugs. Best to stick with that.

 

Just put in 6 OeM Denso last week and have not had enough driving to check gas mileage yet, but engine seems to run smoother. As stated in previous threads about spark plugs, there were 3 Denso in passenger side bank and 3 NGK in driver side bank. Had 75k on original plugs and was getting consistent 20 mpg +- few tenths, original plugs were just worn down, looked actually good and dry, electrode just worn. Went to dealer to buy at about $3.50 as. plugs at local auto parts were higher. Tacoma Parts Express was $2.88 but $8. shipping.

 

Something is wrong with either how the plugs were installed or tge plugs themselves.

If you don't know how to search for or fix this problem take it to a trusted shop right away and have them look at it. Best not to risk cylinder failures buy you driving it with an obvious issue.

Has nothing to do with tge plugs being irridium.

 

Just curios, what is the difference in an engine designed for std spark plugs vs Iridium spark plugs?

 

That’s what I was taught. The resistance in a copper plug is less and so the spark jumps the gap easier. Iridium and platinum ignition systems have increase voltages to compensate for the increased resistance.

 

The air gap is virtually the same and that is what determines the voltage required to bridge the gap. If the ignition system puts out enough voltage to overcome the internal resistance of the spark plug there is no difference in performance of the plug.
It is interesting that none of the searches I have done on performance upgrades for the 1GFRE recommends an upgrade for the ignition system. Of all the available replacement coils I could find online none were advertised as having greater voltages than the stock Toyota coils. All are advertised as OEM equivalent.