What a difference changing spark plugs makes!

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Every I4 I ever owned shaked and vibrated. Some more than others. A v6, v8 is better balanced during operation. The plugs help, but there are some other things that will help as well. Replace the mounts (motor and trans) and all intake related gaskets. Oil weight and brand is important too. Don't make a small engine struggle in the thick stuff.
 
Changed plugs in my Gen Coupe yesterday. 87k miles on the old ones Denso OE TT iridium.

Really perked up the acceleration. Maybe because of me clearing the ecu maps too after it's been sitting all winter.
 
Originally Posted By: Reddy45
Might be a Ford thing? I noticed a similar improvement in my old F150 when I swapped out the plugs.


Not on my Ford. As I mentioned last August:

Originally Posted By: oldmaninsc
I changed the plugs in the Grand Marquis at about 140,000 miles, and it made no difference in MPG or power. At 140,000 miles, the plug gap was pretty wide, but it passed the California smog test a couple of months before I replaced the plugs.
 
Originally Posted By: 2strokeNorthstar
Track? Drag-strip? Yaris?


Yessir. Fastest thing I own (that runs). We run anything.

Took it up with my hoosiers to try to get upper 15s. But with the loss of power I only just barely squeeked out a new PB of 16.31.

https://youtu.be/pgDCNfNJkMg
 
Originally Posted By: sh40674
changed plugs on a buddys 10' edge, the car was right at 100k. can't remember specifically the gaps, but the old plugs were about .050 over stock lol. huge difference when changing the plugs. he said better mileage and ran a lot better.

for comparison my dodge ram eats plugs at 30k. i try to change them every 25k. they'll be .030-040 over gap when i change them, and when i have the new ones in i don't notice a difference at all. a little smoother idle, that's about it.

maybe it's a ford thing?


Those are probably copper plugs, not Platinum or Iridium.
 
Originally Posted By: thooks
Originally Posted By: sh40674
changed plugs on a buddys 10' edge, the car was right at 100k. can't remember specifically the gaps, but the old plugs were about .050 over stock lol. huge difference when changing the plugs. he said better mileage and ran a lot better.

for comparison my dodge ram eats plugs at 30k. i try to change them every 25k. they'll be .030-040 over gap when i change them, and when i have the new ones in i don't notice a difference at all. a little smoother idle, that's about it.

maybe it's a ford thing?


Those are probably copper plugs, not Platinum or Iridium.





dodge specs copper plugs, yes, so 30k makes sense. mine should be platinum or iridium from the factory, should still be fine at 65k lol
 
Originally Posted By: oldmaninsc
Originally Posted By: Reddy45
Might be a Ford thing? I noticed a similar improvement in my old F150 when I swapped out the plugs.


Not on my Ford. As I mentioned last August:

Originally Posted By: oldmaninsc
I changed the plugs in the Grand Marquis at about 140,000 miles, and it made no difference in MPG or power. At 140,000 miles, the plug gap was pretty wide, but it passed the California smog test a couple of months before I replaced the plugs.


I can't believe I forgot what you told me last August!
 
Placebo effect, for the most part.

I have the tendency to think the same sorts of things when I replace something.

I replaced the plugs on my Taco last week. Went back to factory (standard) plugs after having installed a set of Autolite Iridium XP back in 2012. They were in for about 110,000 miles. Factory manual calls for regular plugs and changing every 30,000 mi. Little bit of a nerve-wracking experience, removing plugs after 6 years. Nevertheless they all came out fine. Gap was out of spec on all of them.

Idle was marginally improved, as well as starting. To me, throttle response seems a bit sharper, but this is probably all in my head.

Went with Denso plugs, as, back in 2012, the truck had Denso on one side and NGK on the other from the factory (apparently this is pretty standard practice for Toyota). The electrodes on the Denso plugs looked more substantial to my eyes than the NGK after being in for around 90K. But, then, it's possible that the NGK are thinner originally. I'd have to compare new ones side by side to see, for sure.
 
My mustang noticed an improvement changing plugs around 60k miles. For me the changes were smoother idle, better throttle response, and slight fuel economy improvement. This was just with stock replacement motorcraft plugs.

I've also noticed benefits of changing plugs on plenty of other cars, at almost any mileage (nothing extremely short).
 
A lot of old British motorbikes would only run properly with one particular make of plug. Never mind other makes had the same heat range, and apparently were identical in every way, and according to many catalogs were interchangeable.

Claud.
 
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Originally Posted By: john_pifer

Went with Denso plugs, as, back in 2012, the truck had Denso on one side and NGK on the other from the factory (apparently this is pretty standard practice for Toyota). The electrodes on the Denso plugs looked more substantial to my eyes than the NGK after being in for around 90K. But, then, it's possible that the NGK are thinner originally. I'd have to compare new ones side by side to see, for sure.


Toyota did this with waste spark engines. They did it because they could put platinum or iridium on one set of electrodes and platinum or iridium on the other set of electrodes. That is often why original Toyota spark plugs look different from replacement plugs.
 
Originally Posted By: artificialist
Originally Posted By: john_pifer

Went with Denso plugs, as, back in 2012, the truck had Denso on one side and NGK on the other from the factory (apparently this is pretty standard practice for Toyota). The electrodes on the Denso plugs looked more substantial to my eyes than the NGK after being in for around 90K. But, then, it's possible that the NGK are thinner originally. I'd have to compare new ones side by side to see, for sure.


Toyota did this with waste spark engines. They did it because they could put platinum or iridium on one set of electrodes and platinum or iridium on the other set of electrodes. That is often why original Toyota spark plugs look different from replacement plugs.
Ford did this too with waste spark in the 80's and 90's. They used double plats on bank one, the ground firing bank, and single plats on bank 2.
 
My wife Nissan Versa Note is just around 50,000 miles. I have noticed a recent drop in gas milage. I wonder now if it could be plug related. I will keep an eye on that now that summer gasoline blends are coming back. I for one am personally inclined to do preventative maintenance early. So changing relatively cheap spark plugs isn't a financial problem for me.
 
Originally Posted By: artificialist
Originally Posted By: john_pifer

Went with Denso plugs, as, back in 2012, the truck had Denso on one side and NGK on the other from the factory (apparently this is pretty standard practice for Toyota). The electrodes on the Denso plugs looked more substantial to my eyes than the NGK after being in for around 90K. But, then, it's possible that the NGK are thinner originally. I'd have to compare new ones side by side to see, for sure.


Toyota did this with waste spark engines. They did it because they could put platinum or iridium on one set of electrodes and platinum or iridium on the other set of electrodes. That is often why original Toyota spark plugs look different from replacement plugs.


My 1996 Contour 2.0L Zetec came from the factory with platinum pucks either on the ground electrode or the firing electrode due to being a waste fire ignition. The Motorcraft replacement plugs had platinum pucks on both the ground and firing electrode. I guess the factory plugs with the single platinum puck electrode instead of both electrodes having platinum pucks was a cost saving measure on Ford's part
grin.gif
.

Whimsey
 
Originally Posted By: jj51702
Spark plug placebo effect


I don't think so. Even after driving a lot more the instant MPG counter is still about 0.8MPG better than it was before. So not quite the 1.5MPG-2.0MPG improvement it was quoting originally, but still, the plugs will pay for themselves easily. And idle smoothness and throttle response is still better even after it had a chance to relearn everything. Only thing is I think my AC isn't working well at this point. Gosh, I have the worst luck in cars! lol
 
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Just this morning I changed the plugs in my DD 2010 Hyundai 2.4L with 146k+ on the clock.

I didn't originally plan on it as the plugs were changed @ 105K. I was recovering from surgery so I had a shop do it then. But a few times I got a CEL for cylinder 4 misfire. I'd clear it and it would return a couple months or so after. Would only happen 1st early morning start right away. I'd check with Torque Pro & clear it. Then a few months or it returned. Like a single misfire - couldn't tell by feel or hear anything.
So today I pulled out Denso plugs and noticed the ground electrodes were growing a little tip toward the electrode. The gap was narrowing. I put in NGK Iridium plugs. And since I had a set of new OEM coil packs might as well replace the coil packs. Plus changed out engine air filter and cabin air filter.
Although the removed Denso plugs only had 40k I hope the new NGK Iridium plugs, new coil packs and a fresh filter does me good (can't hurt). Just this afternoon driving it does seems a little bit smoother at idle in gear. Actually hoping the CEL stays clear - it should now.
 
Originally Posted By: Errtt


So today I pulled out Denso plugs and noticed the ground electrodes were growing a little tip toward the electrode.


Today I learned the Denso plugs I pulled out were Denso TT. The TT are Twin Tip plugs. Something I didn't know.
Was told they been out about 3 years. Oh well, no matter I threw in my go-to plugs "NGK Iridium".
 
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