Just purchased 2000 Express 3500 with 88k miles. It has a 5.7 Vortec. I'm sure age has a consequence in my question but at what mileage would I expect to go after spark plugs, plug wires and distributor cap? Van is a Roadtrek conversion van. I am able to do this work. Just dont want to crawl around over and under this for minimal gains.

 

When it starts to run rough. There's so much plastic under there that just breaks when you mess with it, the less messing with it the better.

 

When does the owners manual say it needs a tune-up? I'd do it then. I've never had good luck removing plug wires so I always replace them and save the longest one I don't break for just in case.