Platinum plugs?

After two years or 30,000 miles, pull them. If they look fine, put them back and look again in another 30,000.

But make sure they are clean and the gap is good. You can't check too often.

--scott

Read the manufacturer's data.

If it's running ok there is no reason to change them for at least 50K. I don't like to go more then the 50K because I like to get a look at the plugs to see if all cylinders are still burning cleanly. Then put a new set in and do it again at another 50K.

The change interval for Bosch platinums is about 50 feet.

I've used Bosch in half a dozen cars and never had a single problem.

I have taken them out of half a dozen that 'did' have problems...

For some reason they really don't want to work in Jeep 258 engines and some 4.0 Jeep engines.

Mike

Did those engines have a tendency to ping a lot?

These engines are touchy about the correct timing and fuel grade to the point of the owners manual recommending high test for hot dry loaded running to avoid pinging or to even lessen the load if needed. This is 'with' a knock sensor in some also.

With the Bosch platinum plugs, they develop misses all the way up and a 'bad' idle miss.

Mike

Additionally platinum plugs are susceptible to fouling in "old-tech" engines and don't seem to self-clear at all. I'd recommend sticking with regular plugs of good quality and simply replacing them more often.

nate

Over the years, I have tried several different brand names of spark plugs, such as Champion, AC, Autolite, Bosch, Splitfire.I found that Autolite spark plugs work best for me. cuhulin