Scotty, my 2003 lexus sc430 has 70k miles. the owners manual says to change the spark plugs at 120k. should i wait until 120k or change them now based on the 20 year age of the plugs. also, rock auto has these newer plugs made from Ruthenium, it shows higher fuel economy and performance with them vs the others. is it safe to put those plugs on my car? what do you recommend? thank you..
Why you can use those spark plugs if you want but I wouldn't waste my time yet because they shouldn't be worn out. And it's going to cost a bunch to change the back three spark plugs because you have to change the intake manifold off in order to get to them. So it's an expensive endeavor and if it's running fine you don't need to do it for quite some time
Car runs fine. Thank you sir