When To Change Spark Plugs

[Sierrawolf]

Hey all i have a 03 sierra 4.8 v8. Im at 53467 miles and woundering when do you change your spark plugs ? I was told a while back to not even bother to touch them or you would get problems. But what made me wounder thi my check engine light came on today and got me thinking what stuff needs to be changed out and what not. So does anyone got any info into doing a overhaul on your truck?

[Nytemare]

First of get the code read, its probably a O2 sensor.

 

I changed my plugs a few miles back. I have 75K Km on mine thats about 46K miles. They looked like s**t and I felt it missing on idle. Swapped out the plugs for some NGK TR-55's and some MSD wires. It idles smooth now and feels like it has a little more pep. Mainly because upon metering the wires I found one that was showing infinite resistance, so that means that I was only firing on 7 cyls and some of those plugs looked pretty crappy.

 

I'm a big believer in that pugs should not stay in longer than 25K.

[Nice rig]

You can get 200,000 miles plus out of these motors, the tranny will go first. As for the plugs, is they are factory you should be good for 100,000. Go to your local Auto Zone or other automotive place and have a code reader hooked up...could be something as simple as a bad connection on something.