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Spark plug & wire change

5168 Views 13 Replies 7 Participants Last post by  nathanisrael
I had my spark plugs and wires changed some 80,000 miles ago. I used expensive NGK iridium spark plugs. It is supposed to last over 100,000 miles. Recently I experienced deteriorating gas mileage: only 26-27 miles. There are several factors for that. I cleaned the fuel injector and checked everything else and I found nothing was wrong. I had tried to pull out spark plugs in the past, but I couldn't because the spark plug wire boots were stuck. I finally bought new wires just in case old ones are torn during removal process. I used a channel lock pliers to firmly grip the base of the boot and managed to lift off the boots. When I removed the spark plugs, the gap was wide open and the condition of electrodes were not good. I bought new Champion platinum plugs. They were much cheaper: around one-third of NGK. After changing the plugs and wires, I calculated gas mileage again. Wow! The result was surprising: Now gas mileage jumped to 33.8 miles per gallon! It was great improvement. The odometer hit 275,000 miles today. Now I can drive 400 miles with one fill-up. I don't think I need to buy a new car. My conclusion is that you don't need to spend a lot of money for iridium spark plugs, but buy economical, but dependable Champion platinum spark plugs and check regularly and replace if necessary. Iridium plugs are supposed to last long, but there is a risk if you keep too long in the engine and that they can be stuck and difficult to remove and moreover, they don't really last long.
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The best plugs for our cars are the NGK platinums. As you said it's better to swap the plugs more often then keep them 100k. I would never keep plugs for that long in the first place.
Do you have a scientific proof or reliable data to support your claim that NGK platinum is the best spark plugs?
It's just a consensus from members on here. Some have used Champion. But most of us prefer NGK plugs.
Mlumz, i'm looking to throw in the NGK plat plugs in my 06, what wires do you guys use? and where do you order them from?
The consensus is NGK or OEM plug wires with NGK platinum plugs. (I have NGK wires with NGK iridium plugs right now, gonna be changing to NGK platinum plugs soon).

I ordered mine from ebay but you should be able to get them from any autoparts store.
I'm most likely going with the NGK laser platinums.
Have you ever used Champion spark plugs? I asked you about scientiific data to support your claim that NGK is better, but you just talked about "consensus". I think it's because Hyunda owner's manual preferred NGK plugs. It doesn't necessary mean that NGK plugs are superior. Since I bought new Elanta in 2003, I never had gas mileage over 30 mpg, all with NGK plugs. After I changed to Champion spark plugs, now I have 33.8 mpg. The odometer is now over 275,000 miles. Of cause, there are several factors which affect gas mileage, but I didn't change my driving pattern from the beginning.
I don't have scientific proof. That is why I said the consensus of the forums. I have used champion plugs. But I've used NGK plugs in my Hyundai because that is what was recommended by the community. You are free to use what you feel is the best for yourself. I was just offering info from the community
Congrats to danielelee for keeping the car beyond 200K miles. IIRC, I think the engines were designed to last about 200K miles. I've used NGK's. Regardless of which plug chosen, I usually got around 33/34 mpg. The cheaper plugs worn out faster and I seem to destroy the wires when pulling them out. For the latest batch, I chose iridium over platinum so I won't have to pull the plugs as often - and in the process, destroy the wires.

I usually buy the plugs and wires from local autoshop when they are on sale and using 40% to 50% off coupons. It beats buying from Internet when you have to pay shipping.

Off topic. I think the motto for Elantra should be "it's a car that keeps on going". I drove it over 130K miles and gave it to two of my kids who abused it learning to drive stick. It's hitting 180K. The original clutch is worn and it's due for timing belt replacement soon, but I think I will donate the car then.
Mine is at 180k, OEM plugs and wires are all I have ever used.

When mine is worn down and in serious disrepair it's going in for a complete restoration. I cannot imaging being without an elantra hahaha
I have always used the denso iridiums. It is my one of the favorite brand.
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