gagemcc

Well I decided to check my spark plugs because I can get a rough idle 70% of the time when I start my engine when it's warm, it smooths out on it's on. So I checked them and 4/6 are readying at a resistance of 4k while two others are reading at 8k. They're the Motorcraft Platinum plugs, I was pretty happy to find out my engine is running nicely by the look of the spark plugs considering I have 117k miles but anyway I would imagine resistance matters a huge bit on giving the engine spark; so would you guys agree with me on saying they need replaced?

Sixer4Life

I always replace my plugs every 15-20k miles. Even if I don't have one bad I'll still replace them all. They are inexpensive and easy to replace. So I'd say go ahead and change them. You won't hurt anything by changing them.

KrazyKen

I agree with Sixer4Life, spark plugs are a cheap replacement and helps to keep your engine running optimally. Replace them all at the same time though.

TfcCDR

Remember to use anti-seize on the new plugs. While you're in there, take care of your air filter.