i have 75000 miles on 1 set of spark plugs the denso ones is it time to replace them the truck seems to be running fine

Platinums or regular Nippondensos?

Dealership told me the regulars (K16Tr11) are good for 15K-I have also heard 24K.

Platinums should be good for 90 I hear...

I change my non-plat plugs every 50k. I think the service writer at the local Toyota dealership told me 30k, but it's been fine with the 50k interval. The plugs look good, too.

i replace mine at 30K, i use the denso plugs the dealer supplies and pay no more than $2.00 each. i can replace six of them in less then 30 minutes on my 4runner. cheap insurance if you ask me. i wouldn't prolong them any more than 30k IMHO.

my dad replaced the ones on his honda at 120k miles. lol

well if you think it runs fine then keep them. what kinda mileage are you getting? are you the original owner so you know they have 75K?

i got my 02 with 58K and changed my plugs at 60K. the denso ones in there were pretty much new except the corner one by the driver side. assuming they were changed at 30K which is what the toyota recommends there was very little wear. this is for non-platinum.

I change mine ever 30,000...

However, just last week, I changed out my buddies who had them in for 119,000 miles in his 3.4L T100!! Changed them out and it was like night and day though.

i try to change mine every 50k, i feel comfortable with that and it makes my life easier as i always do it at the same interval.

I suppose it wouldn't be a bad idea to remove, inspect then reuse the plugs if you aren't going to be replacing them. You really don't want the spark plugs to take the threads out with them when you go to replace them 90K down the road.

That said I have no idea what interval you shoud be removing them to prevent the plug from bonding the the threads.

For the little bit that new plugs cost, you are really asking if you should keep using them???

Spend the $12 and replace them. I usually replace mine every 10k miles but then i am a bit overboard with my trucks maintnence.

I understand they last longer than 15K. Thus, replacing them at 10K doesn't make sense now does it.

Not really, but for that little bit of $, it is worth it for me to know that it is done. Plus 10k is about 3 years for my truck, so after that long changing plugs is not a bad idea. I have seen some pretty dirty plugs when i changed them.

I got 130k out of my last set of Denso plugs.