How do you know if ya need spark plugs changed or a tune up on your vehicle(toyo 4runner) 100K miles?

around 60mile per hour it startles a lil bit then, act like it wants to shut off.How do you know if ya need spark plugs changed or a tune up on your vehicle(toyo 4runner) 100K miles?if you have not changed it yet since you first got it then i would change them the generaly rule for changing spark splugs is once a year spark plug wires maybe once every two. try to change both at the same time to try to eliminate the problem if you chagne both and its still the same then you know its something else maybe try to change the fuel filter too at the same time and change oil, and air filter too, all of those are basic tune up stuff that you can do your self.How do you know if ya need spark plugs changed or a tune up on your vehicle(toyo 4runner) 100K miles?Your owners manual has all kinds of information in it. Including plug and maintenance schedules. .............UJNHow do you know if ya need spark plugs changed or a tune up on your vehicle(toyo 4runner) 100K miles?If it has 100,000 miles on it it is due for a tune-up.