Spark plug interval

[pektel]

Just getting a feeler for how long everyone waits until replacing plugs...

I normally go about 50K.

 

[joegr]

Whichever of the following happens first.

1. 100K miles go by.
2. 5 years go by.
3. Another COP fails.
5. MPG goes down (assuming at least 50K miles on the plugs at that time.)

 

[pektel]

Reason I ask is, I replaced them last at 100K. had a COP fail a couple months ago. I'm at 152K now, so about due anyways. Can't get better than about 16 mpg (normal mix is about 17.8-9). Also having an intermittent hard start/misfire problem. Looks like max is gonna get a call today.

 

[Lincoln Jealous]

Reason I ask is, I replaced them last at 100K. had a COP fail a couple months ago. I'm at 152K now, so about due anyways. Can't get better than about 16 mpg (normal mix is about 17.8-9). Also having an intermittent hard start/misfire problem. Looks like max is gonna get a call today.

for plugs or coils?

 

[pektel]

Just changed coils a couple hundred miles ago. Guessing I have a fouled plug, since the intermittent miss has been there ever since. Unless by some chance I got a brand new but faulty coil somewhere in the set.

 

[LS4me]

I've been changing the plugs every 50ishK miles. I don't trust that 100K interval. IMHO, manufacturers are using this interval to show a lower cost of ownership.

 

[Andrizzle]

I'm with Joegr on this.

 

[FASTLLS]

^
Yep.. Dead on..

 

[Missing Linc']

Depends on the car, my T/A I did them with a tune up and oil change every 2500miles. Have yet to change the ones on the Lincoln tho, at 60K now, probably will shortly.

 

[rainjacks]

If I was having your problems I'd take a few out and look at them. If they look solid I'd leave them, but if they look even slightly off I'd go ahead and replace them.