Well, i just ran over 90k on my 97 Sc400 the other day. I've done many searches on what people have replaced during their 90k and the crazy cost involved with a 90k tune up.
I hope to do most of it on my own and the part i can't do, i'll buy discounted parts and pay for the dealers labor. I"m not sure my car was inspected at 60k because i bought it at 70k last year. I've personally inspected the engine and it's perfect...as far as smoothness, hesitation..etc..

My question is, if i have 91k miles on it..and the car is running perfect..should i replace the spark plugs yet?..It's a 97 and it feels strong..
What do you guys think..."don't try to fix something that isn't broke/or getting weak"
BIGd

 

The spark plug on the 97 SC400 is recommend every 60K. If you did change the spark plugs at 60k then you next one is 120K.

 

The most important thing to keep up to date are fluids. People don't change their trans fluid enough and most people change their engine oil too much. Coolant is also important. Don't forget the rear diff either. Most people overlook that.

Spark plugs are very important, but you can get away with inspecting them. If you do a lot of freeway miles and the plugs all have the right color and show no signs of physical damage or wear, then you can keep them. However, if you're going to inspect all of them then you might as well replace them all since their farily cheap. The stock plugs I bought from Sewell lexus were only about $4 each. They are double that at most dealers for the same plug.

We didn't do our first timing belt change until 120K. On toyotas, the worst thing that can happen if you don't change the timing belt soon enough is you could be stranded as no engine damage will occur if it breaks. Our 120K belt looked nearly with no obvious signs of cracking.