Are these spark plugs shot?

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May 17, 2022
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The previous owner put some ngk iridium plugs in my 2000 Corolla. I don’t know how long they have been in there but the car does burn oil and it appears that it also runs lean. I did just get a p0300 code which is a misfire. I felt the car shake for a few seconds but it stopped and drove normal.

If I do change the plugs I will probably just put in ngk platinum plugs just so I don’t waste money putting good plugs in if the car is just going to foul them quicker. What do you guys think?
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carg618

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Doesn’t look lean to me. Looks like ashy deposits. That thing must really be using some oil.
That’s good news to me that it doesn’t look lean. And yessss she goes through her oil. Probably goes through a quart every 400 miles which isn’t the best but nothing else I can do. I can’t afford a new engine at the moment. 2000-2002 corollas has very bad burning issues. The 1998-99 were bad but wasn’t as bad as the 2000-02.

Do you think that cheaper less expensive plugs are ok? I mean, I think that any plug no matter if it’s copper or iridium is going to do well under these engine conditions right?
 

carg618

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That's some ugly spark plugs.
Yes they are. I have no clue how long they have been on there so I am going to assume they need to be changed asap. Car burns a lot of oil especially when coasting down a hill in gear and then giving it gas at the bottom of the hill. It puffs a big cloud of blue lol
 

carg618

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Just keep the oil top up and save your money for an engine replacement. If you keep getting misfire codes I’d put in a new set of copper plugs. No reason to spend the extra cash for iridium’s in this case.
I ended up getting ngk 7090 platnum plugs for $2.50 each but I just realized that the gap is 0.040 while Toyota says this car should have 0.044. Does this little amount matter? Maybe I’ll just keep the order placed and just go to Walmart and buy a $1 gap tool
 
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I ended up getting ngk 7090 platnum plugs for $2.50 each but I just realized that the gap is 0.040 while Toyota says this car should have 0.044. Does this little amount matter? Maybe I’ll just keep the order placed and just go to Walmart and buy a $1 gap tool
Nah that small difference in gap isn’t gonna matter.

Bummer on the oil burning, my aunts 02 Corolla used a quart per fuel tank for years. When it killed the catalytic converter a second time she traded it in.
 

carg618

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Nah that small difference in gap isn’t gonna matter.

Bummer on the oil burning, my aunts 02 Corolla used a quart per fuel tank for years. When it killed the catalytic converter a second time she traded it in.
I’m my case I just cut the catylitic converter because it was destroying them. Luckily in my state, if your car is over 20 years it’s considered a classic and is exempt from emissions.

As for the plugs, I might just buy a gap tool just to have as the preset plugs sometimes could be off. So it’s nice to have. I’d rather get platnum because it’s only 50 cents cheaper and I hear the mpg might be better?
 
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I’m my case I just cut the catylitic converter because it was destroying them. Luckily in my state, if your car is over 20 years it’s considered a classic and is exempt from emissions
Lucky! Good news is you can drive it like that forever then as long as you keep the oil in it. Buy the cheapest oil you can or if you have two cars put the used oil from the other car in there haha.
 
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The plugs are out and they look wasted so just replace them and check in 10,000 miles. Gap isn't a big deal but you can tweek it open if it bothers you with the correct tool. Gut the cat if it gets clogged or just straight pipe it.
 
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Yes they are. I have no clue how long they have been on there so I am going to assume they need to be changed asap. Car burns a lot of oil especially when coasting down a hill in gear and then giving it gas at the bottom of the hill. It puffs a big cloud of blue lol
That's the classic test for oil burning.
 

carg618

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The plugs are out and they look wasted so just replace them and check in 10,000 miles. Gap isn't a big deal but you can tweek it open if it bothers you with the correct tool. Gut the cat if it gets clogged or just straight pipe it.
Do you think that platnum plugs have any advantage over copper other than longevity?
 
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What does that mean? I heard of other people saying that but I’m confused on what it means.

Heat range is how the spark plug dissipates heat to the cylinder head. A colder plug transmits more heat to the head and the tip stays cooler. A hotter plug retains more heat.

A hotter plug might help with oil burning deposits.



EDIT : i got i backwards , a hotter plug has a lower number.
 
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