I just bought new NGK spark plugs and was wondering what you guys think I should use out of the two plugs I have.I have the NGK GP platinum 3403 TR55GP new and still have the ACDelco Professional Platinum Spark Plugs still installed. If you think I should keep the acdelcos I want to test them and see if there still good other then visually looking at them. How can I test them and what readings should I see other then seeing them give spark?

 

eHow: How to Test Spark Plugs

 

I would examine the AC Delco plugs for condition. Is there carbon buildup? Is the gap what it is supposed to be? Are there any cracks on the porcelain? Check to make sure the two platinum pucks are still on the center electrode and the ground strap. I had a problem with the OEM AC Delco plugs when they started losing the platinum pucks. Two sets did that, and I switched to NGK.

Are you having a specific problem with misfires? What leads you to believe you need new plugs?

Just curious - why did you select NGK platinum over NGK iridium?

 

I just got them from a friend for $10 and just thought if I should use them.