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lexus is350 spark plug change outcome

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Old Mar 12, 2012 | 11:52 AM
  #1  
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Question lexus is350 spark plug change outcome

just wondering what was the outcome when the 350 people here change their spark plugs, what you guys notice if better MPG, smoother acceleration or anything else
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Old Mar 12, 2012 | 12:36 PM
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Theoretically, yes. Improved idle, accel, power, mpg, etc. But... ideally, plugs should be changed out before they deteriorate to such a point, so no.
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Old Mar 12, 2012 | 01:01 PM
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I waited till 79,900 to change mine and that was way to late, I had been dealing with some weird idle and sluggish performance for awhile. I bought my car with 59,000 and it runs better then it did when I bought it. Next up is rear end fluid and brake job...
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Old Mar 12, 2012 | 05:57 PM
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Just did mine a week or so ago. Haven't noticed any difference TBH. Did mine at 61k and the original plugs still looked pretty decent.
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Old Mar 12, 2012 | 06:07 PM
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I changed mine out right after 50,000 miles and noticed no difference at all. Acceleration, performance, idling, it was all the same. I thought my fuel economy became better but it was just because the weather was becoming warmer and there was less traffic where I've been driving.
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Old Mar 12, 2012 | 06:57 PM
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Originally Posted by chi123
I changed mine out right after 50,000 miles and noticed no difference at all. Acceleration, performance, idling, it was all the same. I thought my fuel economy became better but it was just because the weather was becoming warmer and there was less traffic where I've been driving.
If I remember correctly from Thermodynamics class, the colder the air the better the mileage, not the other way around. Cold air provides a better heat sink and is denser so you get better compression ratio?
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Old Mar 12, 2012 | 07:21 PM
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This is the only thing left for me to do, just did oil change, filters, news rotors and pads and brake flush.
Hopefully more people will chime in and none had problems
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Old Mar 12, 2012 | 07:23 PM
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I changed mine at 60k. I noticed no difference at all, but I rather have the piece of mind that they are changed
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Old Mar 12, 2012 | 07:23 PM
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Originally Posted by LDNN
If I remember correctly from Thermodynamics class, the colder the air the better the mileage, not the other way around. Cold air provides a better heat sink and is denser so you get better compression ratio?
You're over-thinking this lol. The engine revs higher on cold starts and it takes longer to warm up to operating temperature. It wastes more gas like that. That was like in 40 degree weather. Then it got warm to past 60 and it only took under a minute of driving to warm up unlike normally when it takes 5-10 minutes. Not to mention, maybe gas stations also changed their blends since the seasons were changing.

I understand where you're coming from, which is why people like CAI for intakes. I'm sure a car performs better in temps around the 60's rather than 90's or 30's.
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Old Mar 13, 2012 | 10:26 AM
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I already got mine, should be changing them out sometime this week if i have time. Getting close to 63,000 miles...
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Old Mar 13, 2012 | 07:33 PM
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i just did mine, and it does pick up much better since i bought my car.
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Old Mar 13, 2012 | 08:26 PM
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Originally Posted by chi123
You're over-thinking this lol. The engine revs higher on cold starts and it takes longer to warm up to operating temperature. It wastes more gas like that. That was like in 40 degree weather. Then it got warm to past 60 and it only took under a minute of driving to warm up unlike normally when it takes 5-10 minutes. Not to mention, maybe gas stations also changed their blends since the seasons were changing.

I understand where you're coming from, which is why people like CAI for intakes. I'm sure a car performs better in temps around the 60's rather than 90's or 30's.
And winter fuel takes a bite out of fuel economy.
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Old Mar 13, 2012 | 10:11 PM
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Originally Posted by LDNN
If I remember correctly from Thermodynamics class, the colder the air the better the mileage, not the other way around. Cold air provides a better heat sink and is denser so you get better compression ratio?
No. The colder the air the denser it gets. That translates to more fuel that is injected into the combustion chamber to reach pre-determined ratio. Therefore, you'll get better performance not better MPG.
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Old Sep 6, 2020 | 01:11 AM
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Hey,

Ive changed my spark plugs and wanted to get your opinion on whether the sparks show any bad signs of wear on the engine running.

Im currently at the 100km or 60k miles mark.

I had also torqued my spark plugs to 20ft cause the torque wrench lowest setting I had available was 20ft lb. The recommended setting was 18 from the dealer is it fine even to be a bit over?


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