Iridium vs platinum spark plugs

Can anyone tell me from experience ?

'95 Avalon @ 178k miles. Run well; get @ 24 city/31 hwy. Need to get tune up in a few days. Will mpg’s get better ?

No. Your wallet will get thinner, that’s all…

No benefit, other than extended change interval. I would use the exact brand and stock number that came in your Avalon.

At 178,000 miles you defintely need new plugs, but both platinum and iridium have a very long life. If your curent plugs are worn, you will get slightly better gas mileage with new ones, any new ones. A friend of mine drove his 1997 Taurus untill the “service engine soon” light came on; his plugs were well worn and the car was not meeting emission standards.

On our Nissan we installed iridium plugs at about 90,000 miles and will likely never replace them again.

All plugs should perform the same when they are newly installed. Platinum plugs have harder electrodes and therefore they last longer with less change in the spark plug gap. Iridium plugs are even longer lasting than platinum.

There will be no difference in your mpg unless the old plugs are very old and the electrodes are worn down. There is a debate about the long lasting plugs. Yes, they last but is it a good thing to leave them in the car for 100K miles and 5 or 10 years? Plugs that are in a motor a long time can be difficult to remove and may damage the threads in the cylinder heads. Some users of the long lasting plugs take them out and reinstall them every couple of years. Some just leave them in place and hope.

Best advice is to use the exact same plug that came from the factory when replacing spark plugs. Then follow the interval recommended in the owner’s manual for replacing them.

I second putting in the same plugs the engine came with new.

Replace the plugs with those recommended by NGK for your car. Use NGK or Nippon-Densa, however, and not an off-brand. These are the only two companies that Toyota uses as original equipment suppliers, so you know they’ll have the exact replacement. Put something like Champions in and you’re sure to have problems…I speak from experience.

No. you’re ont likely to see an increase in mpg. If your plugs were badly worn enough for that to happen you’d not be getting those mileage figures in that car and you’d probably have see a CEL by now.

I recommend using the same brand and model plug that came with the car. Don’t try to get more miles out of it. The longer a plug stays in that engine the greater chance of having it freeze in there and it can be a lot of work trying to get it out. Plugs, even platinum plugs are cheap in the long run.

Different brands may have a slightly different thread and buying a different brand may cause problems

When I replaced the plugs on my 4runner for the first time I found the drivers side had Deso plugs and the passenger side had NGK plugs. I replaced them with NGK.

There is ZERO difference in performance with either using Regular copper, Platinum or Iridium plugs. They perform exactly the same. HOWEVER…the Iridium plugs are designed to last OVER 100k miles…the Platinum’s - about 90k miles and the regular copper - about 60k miles.

My wifes Lexus…the ONLY plug available is the Iridium from Denso. NGK doesn’t even make a plug for that engine. Dealer wanted $24 per plug…I bought them for $13.