Home Forums Hunting & Shooting Hunter's Campfire Newer vehicles.

As in later generation, not new. Got a chevy truck with around 150,000 on it, and a chevy car with more miles on it than that. Never changed the plugs in either one of them. Car was purchased new, truck with 29,000 on it. Fuel mileage is still right there with what they both done when we got them. Run em' till they start missing or show a drop in fuel mileage, or change the plugs in them at a certain point regardless?

I have a 2014 Ram with a hemi. Dodge recommended or suggested I change them at 25,000 miles. There are 2 per cyl and they wanted $400 to do the
Job. I'll do it myself for probably less than $60. I have 95k miles on it now. But, asked the tech how long I really had before I changed them and he said wait until my mileage drops. He said 25k is unreasonable on new trucks.

With that many miles I'd probably just go ahead and change the plugs if I had an afternoon free. I wouldn't run out and fall all over myself to get it done right now however. I base this on a couple of cars of mine, one a 95 honda civic that gradually lost a little power and lost some fuel economy between 150,000 and 175,000 miles. It still ran fine but I scratched my head a bit why I wasn't getting the mileage I used to get. On a whim I decided to change the plugs and I got the mileage back & picked up some power that I'd forgotten was supposed to be there.

The other was a 2005 toyota camry that started taking a little longer than normal to start and was idling rough at around 200,000 miles. I was scratching my head about that one too and thought about taking it to my mechanic but decided to try swapping plugs before I did. The original plugs were in the motor, I swapped them out and the motor returned to starting and running like new. When I looked at the old plugs they had worn down to about 4X the specified gap so it was easy to see why it wasn't running right.

That was the only time I ever changed the plugs in either of those vehicles. The civic got sold off at 275,000 miles and was running fine, the camry at 300,000 and it was running fine too.

There is a whole host of things that they made better in the old days than they do now, but these new motors are quite the technical marvel. Especially as it relates to the electronics. I'm old enough to remember adjusting points about every time you changed the oil, sometimes sooner, changing plugs on a regular basis, changing plug wires, replacing condensers and points, etc.

I changed the plugs on my 1999 F150 with the 5.4 engine at 100k miles as instructed by Ford. They actually looked surprising good being 13 years old and the truck ran noticeably better after the replacment. I changed the plugs on my wife's 2010 Porsche at 20k with Porsche advising to change at 30k or every 4 years. At 7 years the plugs looked like chit and there was a noticeable bump in performance that I had not realized I had slowly lost. I typically follow the OEM's recommendation and certainly will going forward on the Porsche. I do all of my own work so the costs is just a set of plugs.

My cheve says every 100000 miles to change plugs.

As mentioned above, the poor performance kinda creeps up on you over time.

Even a vehicle running "fine" at 150,000 with the factory plugs will probably run better with a little tune up.

Anywhere in that 100,000 to 150,000 is a good time to change the plugs. Cant hurt anything, and those original plugs dont owe you a thing now.

And the plug wires - I've had Chevy mechanics tell me the wires go bad well before the plugs.

Maybe I's better change them in "The Warden"s truck ~ 180K and never done !

One bad side effect of running plugs till performance drops off is the toll it takes on the coil. An out of spec large gap can and will hurt them. I have seen it on a Honda Civic, Ford Taurus, and Toyota Tundra. It's best to change them at least as specified by the Mfgr, if not sooner.

Good point, Kecatt, that's something to keep in mind. I heard tell that once they took the lead out of the gas, the plugs last a whole lot longer. My Dodge has 248k, and the original plugs. The dealer first told me to change them at 60k, but at almost 500 bucks, I said I'd wait till a problem developed. Kecatt's good point notwithstanding, the old beast is still running strong.

What are "plugs"??

A hotter spark will get a faster, more complete burn. The gap is calculated to get the most efficient spark so if you don't change them, at least re-gap them.

That's what I was thinkin!

Yep that's perfectly understandable. Only thing is if you are going to the trouble of pulling the plugs might as well just change them while they're out. I'll change them out in the next month or so. But I will say that when I got the truck with 29,000 on it I immediately turned it into a work truck with a heavy construction cap ect. Early on I checked the fuel mileage regular and on a trip I would average mid 16's. Occasionally I would hit somewhere in the 17's, and 1 time and 1 time only I hit 18mpg. About a month ago I was doing a job that I was running the interstate for about 5 wks back and forth. I checked several tanks of gas and the mileage varied from a low of 16.3 to a high of 16.7. Right there where it averaged 10 yrs and 120,000 miles ago. Amazing.

Ford does, too. The last Ford I sold, a Sportrac, had 215K on it and I had never changed plugs. It was still getting 18 mpg that it did new.

For a vehicle to get the same mileage as it did new is not a really reliable indicator.

Today's engines are so good that they are really just hitting their stride at 100,000. You might find mileage increases with new plugs. Better than when it was new? Yes. Mileage at new is usually lower than what can be expected once the engine is broke in.

This is why I am growing to hate the campfire.

This is ABSOLUTELY true on heavy duty diesels. We see as much as 3% increase on a new semi truck after about 25,000 miles. Some of that has to do with the tires being broken in, but the engines do seat and run more economical and stronger.

Changed the Miata's plugs at 61,000 and noticed a nice bump in performance. The Murano has 78,000 and is running better now than when new. The Frontier is just getting broken in at 51,000.

When my mother quit driving in '07, I bought her '04 Pontiac Montana. It had 60k then and it has 170k now. The engine has never been worked on and has got about 24 mpg since I've had it. It's not a classy car by any means but it's been as reliable as any I've ever owned.