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Spark plugs
November 17, 2007
Ok, once again another question.

im gonna hit 18,ooo miles soon, and i plan to replace my stock spark plugs with the ones that have like 4 prongs (i think they are bosh). I really need yall's opinion and help. THanks!

November 17, 2007#1
For your car, I'd recommend sticking with the OEM Iridium plugs. The multiprong plugs like Bosch+2 or Bosch+4 plugs have a bad reputation on our engines. Some cases, the prongs are not gapped correctly from the box, causing misfires and driveability issues. In some rare cases - the ground electrodes can actually fatigue and break off. Not a pleasant situation for your cylinder walls.

I'd keep the OEM plugs - they are supposed to be good to 120K miles anyways. On my cars, I changed the 1ZZ-FE Corolla ones at a little more than 90K miles (original plugs were still OK, so I kept them as spares) - the ones on the Matrix XRS (2ZZ-GE) started to look a little rough at 75K miles, so I replaced with with the same.

November 22, 2007#2
Thanks. So is their any "performance" spark plug for the Corolla, or which Brand of Spark plug is good for the Toyo. Thanks.

November 24, 2007#3
Unfortunantly, there is no such thing as a "performance" plug regardless of what people say - a sparkplug alone cannot add power. There are ways to "trick" the ignition system to fire a more aggressive spark, but usually at the cost of component lifespan.

But you can get a plug that is less likely to foul or easier to spark - in that case, you lessen the probablity for a misfire which equals loss of power.

For the 1ZZFE powered Corolla - the OEM Iridium plug is the best compromise from either NGK or Denso. Long lasting plug (~120K miles) that is easy to spark and has a fairly open flame kernal. Only better design would be the very thin wire Iridium plugs (ex. NGK Iridium IX line of plugs). They have superior anti fouling, very open flame kernal, and very easy ignitability (basically, the plug will almost always spark when asked to). The trade off with this design is shorter lifespan - usually lasting only 30K-60K before they wear out.

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